Year 12s: what will be the first way you research your future options? >>

Simultaneous equations

IFoundWonderland

Solve the following simultaneous equations:

Reply 1

JohnnyDavidson

Hi, you're factorising is wrong just after the line "ac =" (what exactly does this mean btw?)

Reply 2

Notnek

Original post by IFoundWonderland

Solve the following simultaneous equations:

ii.

You have factorised

-3y^2-3y

to get

-3y(y+3)

. This is incorrect - have another go.

Your method will work but I would have taken out a factor of 3 from the quadratic (and moved everything to the other side) to make it simpler.

Reply 3

Notnek

Original post by JohnnyDavidson

Hi, you're factorising is wrong just after the line "ac =" (what exactly does this mean btw?)

This is the 'ac' method of factorising quadratics.

'a' and 'c' are coefficients of a quadratic equation :

ax^2+bx+c=0

Reply 4

IFoundWonderland

Original post by JohnnyDavidson

Hi, you're factorising is wrong just after the line "ac =" (what exactly does this mean btw?)

Original post by notnek

ii.

You have factorised

-3y^2-3y

to get

-3y(y+3)

. This is incorrect - have another go.

Your method will work but I would have taken out a factor of 3 from the quadratic (and moved everything to the other side) to make it simpler.

Thanks - got it now :h:

And ac is when ax^2 +bx +c

Reply 5

TeeEm

Original post by IFoundWonderland

Thanks - got it now :h:

And ac is when ax^2 +bx +c

you have very neat workings !!

Reply 6

XxKingSniprxX

Original post by JohnnyDavidson

Hi, you're factorising is wrong just after the line "ac =" (what exactly does this mean btw?)

AC just means the first constant value e.g 2x^2-5x+3=0 -> Ax^2+Bx+C=0

A = 2 from 2x^2 and C is the last value C = 3 .*. AC = A . C = 2x3 = 6 -> AC = 6

It just helps writing down to figure out numbers that would factorise. i use the same method myself.

Reply 7

IFoundWonderland

Original post by TeeEm

you have very neat workings !!

Haha, thanks :ahee:

I try to keep it as neat as possible because It makes it easier to check when I make mistakes :tongue:

although it tends to go to pot when the maths actually gets complicated and I'm doing things like further calculus or geometry.

Idk why but this compliment made my day :lol:

Reply 8

Notnek

Original post by IFoundWonderland

Haha, thanks :ahee:

I try to keep it as neat as possible because It makes it easier to check when I make mistakes :tongue:

although it tends to go to pot when the maths actually gets complicated and I'm doing things like further calculus or geometry.

Idk why but this compliment made my day :lol:

You like to keep inside the boxes!

I had a student who would put everything in a box. Their calculus working was neat but quite strange to look at :smile:

Reply 9

Zacken

Original post by IFoundWonderland

Haha, thanks :ahee:

I try to keep it as neat as possible because It makes it easier to check when I make mistakes :tongue:

although it tends to go to pot when the maths actually gets complicated and I'm doing things like further calculus or geometry.

Idk why but this compliment made my day :lol:

Small tip: for maths, it's incredibly helpful to leave a blank line between each line of working for complex calculations! It's makes correcting things, and finding errors much easier as well as just improving the general aesthetic, in my opinion! But yours is very nice as is! :h:

Reply 10

IFoundWonderland

Original post by notnek

You like to keep inside the boxes!

I had a student who would put everything in a box. Their calculus working was neat but quite strange to look at :smile:

Yess it makes it look so much nicer and everything is in line :tongue:

I keep everything in boxes for calculus too :tongue:

but that squiggly line thing at the beginning that shows it's integration (idk what it's called) takes up three boxes height wise and two width wise, so I use so much paper :argh: