# Help with coordinate Geometry

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I want to do maths A levels and i'm doing the step up course now, everything is going well until my teacher gave me some exam style question on this topic and feel like not taking maths after all. it's stressing me that i dont know how to do it.

Im making this thread to post questions that im not sure of, please help check/show me steps etc thanks!

Im making this thread to post questions that im not sure of, please help check/show me steps etc thanks!

1st question is:

Find equation of straight line that passes through the points (3, -1) and (-2, 2)

give your answer in form of ax+by+c=0

hence find the coordinates of the mid-point of intersection of the line and the x-axis

what i got so far is you find the gradient

-2-3 = -5

2 - -1 = 3

so -5/3 which i've put into y=-5/3x + c

i substitute a point in 2 = -5/3 * -2 + c

which becomes 2 = -10/3 + c

and now im stuck

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#3

(Original post by

1st question is:

Find equation of straight line that passes through the points (3, -1) and (-2, 2)

give your answer in form of ax+by+c=0

hence find the coordinates of the mid-point of intersection of the line and the x-axis

what i got so far is you find the gradient

-2-3 = -5

2 - -1 = 3

so -5/3 which i've put into y=-5/3x + c

i substitute a point in 2 = -5/3 * -2 + c

which becomes 2 = -10/3 + c

and now im stuck

**ihatePE**)
Spoiler:

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I want to do maths A levels and i'm doing the step up course now, everything is going well until my teacher gave me some exam style question on this topic and feel like not taking maths after all. it's stressing me that i dont know how to do it.

Im making this thread to post questions that im not sure of, please help check/show me steps etc thanks!

Im making this thread to post questions that im not sure of, please help check/show me steps etc thanks!

1st question is:

Find equation of straight line that passes through the points (3, -1) and (-2, 2)

give your answer in form of ax+by+c=0

hence find the coordinates of the mid-point of intersection of the line and the x-axis

what i got so far is you find the gradient

-2-3 = -5

2 - -1 = 3

so -5/3 which i've put into y=-5/3x + c

i substitute a point in 2 = -5/3 * -2 + c

which becomes 2 = -10/3 + c

and now im stuck

so y-y1=m(x-x1) so y+1=3/5(x-3) which equals 5y-3x+14=0

Midpoint is (x1+x2)/2,(y1+y2)/2 so (3+-2)/2,(-1+2)/2 so 0.5,0.5

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(Original post by

gradient = up/across... you have done across/up

**the bear**)gradient = up/across... you have done across/up

y=-3/5 x + c

2 = -3/5 *-2 + c

2 = 6/10 + c

now what :/

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#5

use this one

y-y1=m(x-x1) where (x1,y1) is a coordinate and m is gradient

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(Original post by

if your doing a level maths then your doing wrong equation formula

use this one

y-y1=m(x-x1) where (x1,y1) is a coordinate and m is gradient

**ElectronDonor**)if your doing a level maths then your doing wrong equation formula

use this one

y-y1=m(x-x1) where (x1,y1) is a coordinate and m is gradient

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#7

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#8

then write

y = -3/5x + your value of c

remember they don't want fractions, so you will need to multiply through by a number.

this method is perfectly fine for A level, despite what other people ^^^ may say

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#9

(Original post by

i havent got taught that formula T_T what does this equation help you find in general?

**ihatePE**)i havent got taught that formula T_T what does this equation help you find in general?

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#10

**ihatePE**)

i havent got taught that formula T_T what does this equation help you find in general?

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(Original post by

it help you find the equation of a line, it is the one you a taught in a level maths, do you know what examination board your college/sixth form does for maths

**ElectronDonor**)it help you find the equation of a line, it is the one you a taught in a level maths, do you know what examination board your college/sixth form does for maths

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(Original post by

just subtract 0.6 from 2 to find c...

then write

y = -3/5x + your value of c

remember they don't want fractions, so you will need to multiply through by a number.

this method is perfectly fine for A level, despite what other people ^^^ may say

**the bear**)just subtract 0.6 from 2 to find c...

then write

y = -3/5x + your value of c

remember they don't want fractions, so you will need to multiply through by a number.

this method is perfectly fine for A level, despite what other people ^^^ may say

do i rearrange now to get it into the format they want?

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#13

(Original post by

We do WJEC at A-level maths , so that equation is like y=mx + c but would be more helpful in cases like this right?

**ihatePE**)We do WJEC at A-level maths , so that equation is like y=mx + c but would be more helpful in cases like this right?

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(Original post by

Yeah i personally believe it is because you make less mistakes through steps

**ElectronDonor**)Yeah i personally believe it is because you make less mistakes through steps

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#15

(Original post by

when do you recommend using this formula? when they give me one points or two points or what type of questions?

**ihatePE**)when do you recommend using this formula? when they give me one points or two points or what type of questions?

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(Original post by

Do you understand how to do rest?

**ElectronDonor**)Do you understand how to do rest?

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Bump

hai! i need help with this question if anyone wants to help

Point A is (1,7) and B is (3,1)

midpoint of AB is P.

find the equation of the straight line which passes through P and which is perpendicular to the line 5y +x=7

i've found P has coordinate of (2,4) using the midpoint rule,

i also did equation of AB which is y = -3x + 10

i've found one of the coordinates for equation 5y + x = 7 and it's (7,1.4)

but then im stuck on what to do next with all these discoveries...any clue?

hai! i need help with this question if anyone wants to help

Point A is (1,7) and B is (3,1)

midpoint of AB is P.

find the equation of the straight line which passes through P and which is perpendicular to the line 5y +x=7

i've found P has coordinate of (2,4) using the midpoint rule,

i also did equation of AB which is y = -3x + 10

i've found one of the coordinates for equation 5y + x = 7 and it's (7,1.4)

but then im stuck on what to do next with all these discoveries...any clue?

0

reply

Report

#20

(Original post by

Bump

hai! i need help with this question if anyone wants to help

Point A is (1,7) and B is (3,1)

midpoint of AB is P.

find the equation of the straight line which passes through P and which is perpendicular to the line 5y +x=7

i've found P has coordinate of (2,4) using the midpoint rule,

i also did equation of AB which is y = -3x + 10

i've found one of the coordinates for equation 5y + x = 7 and it's (7,1.4)

but then im stuck on what to do next with all these discoveries...any clue?

**ihatePE**)Bump

hai! i need help with this question if anyone wants to help

Point A is (1,7) and B is (3,1)

midpoint of AB is P.

find the equation of the straight line which passes through P and which is perpendicular to the line 5y +x=7

i've found P has coordinate of (2,4) using the midpoint rule,

i also did equation of AB which is y = -3x + 10

i've found one of the coordinates for equation 5y + x = 7 and it's (7,1.4)

but then im stuck on what to do next with all these discoveries...any clue?

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