Question

Solve the simultaneous equations 4 x + 3 y = − 10 4 x + y = − 14

Answer 1

x = - 4, y = 2

Explanation:

First equation: 4x + 3y = - 10

Second equation: 4x+y= - 14

To solve simultaneously:

Rearrange one of the equations and substitute the equation to another equation, I prefer rearranging the second equation because it is easier.

Rearranging the second equation to get y, and then substitute back to the first equation to find x:

y = - 14 - 4x ------> new second equation

Substitute y (new second equation) into the first equation to find x:

4x +3(-14 -4x) = - 10

4x - 42 - 12 x = - 10

- 8x - 42 = -10

-8x = - 10 + 42

- 8x = 32

8x = - 32

x = - 4

Now we substitute x = - 4 to the second equation to find y:

4x + y = - 14

y = - 14 - 4(-4)

y = - 14 - (-16)

y = - 14 + 16

y = 2