Question

Solve, using linear combination.

3x + y = 4
2x + y = 4


(-1, 7)

(0, 4)

(-3, 12)

(-3, 13)

Answer 1

Well there are two options to use substitution method or elimination method, I'm sure you are aware of this.

Answer 2

yes i am

Answer 3

I'll be using the substitution one in this case.
1) 3x + y = 4 I am going to rearrange to y =ax + b form
y = -3x + 4
sub y = -3x + 4 into second equation

2x + y = 4
2x + (-3x + 4) = 4
2x -3x + 4 = 4
-x = 0
x = 0
sub x = 0 back into either equations to find y
2x + y = 4
2(0) + y = 4
0 + y = 4
y = 4

so (0,4) and the second answer.

Answer 4

oooooo i get it now thank you :)

Answer 5

no problem :) and remember you can always check with these type of questions if you have got it correct or not by subbing back the x and y values you obtained into the equations.

Answer 6

ok thank you :)