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Help with Higher maths.

Hi, struggling to get my head round questions involving y-b=m(x-a).
Can anyone help me as to how one such a question is done.:s-smilie:

P.S. My main problem lies with how I get to the final equation.

Thanks, Andrew
Reply 1
Avatar for Mc^3
Mc^3
2
is this just a piece of normal, linear algebra? if so, add b to both sides to get y= mx-ma+b
FlyingScotsman
Hi, struggling to get my head round questions involving y-b=m(x-a).
Can anyone help me as to how one such a question is done.:s-smilie:

P.S. My main problem lies with how I get to the final equation.

Thanks, Andrew


Don't really understand your question, obv this equation relates to gradient and points on a staight line!

once you do the first part of the questions you'll get an answer for the gradient (which is represented by m)

the x coordinate of any point on the line is represented by letter a, whilst the y coordinate of the same point on the line is represented by letter b


HERE'S AN EXAMPLE BELOW

Q. What is the equation of the line AB, where A = (2,3) and
B = (4,5)


A. FIRSTLY WORK OUT GRADIENT OF AB

m.AB = y2 - y1/ x2 - x1
= 5 - 3/ 4 - 2
= 2/2
m.AB = 1

NOW WORK OUT EQUATION OF LINE

For point on the line i will use A: (2,3) which remember in this equation is represented by ( a, b)

y-b = m(x-a)
y-3 = 1( x-2)
y-3 = x-2
y = x-2+3
y = x + 1

Therefore equation of AB is y = x+1

Hope this helps :smile:
Reply 3
Avatar for FlyingScotsman
FlyingScotsman
OP
Thanks very much for your help guys!
ScottishShortiex- your example was really helpful- i think i've just about got the hang of it.
However, i'm still not entirely sure how switching numbers/letters to the other side of the = sign works. Do you always swap from left to right? How do you know which number/letter should swap sides? I can see that a positive no. changes to a negative no. if placed on the other side but i need more help as to which number swaps. Thanks- hope you understand my problem

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