Question

Solve the system of equations using the substitution method pls show work

4x+y=7
3x+2y=9

Answer 1

x = 6/5 or 1.2 y = 11/5 or 2.2

Explanation:

4x + y = 7

y = -4x + 7

y = 7 - 4x

3x + 2y = 9

3x + 2(7 - 4x) = 9

3x + 14 - 8x = 9

-5× + 15 = 9

-5x = 9 - 15

-5x = -6

x = -6/-5

x = 6/5

4x + y = 7

4(6/5) + y = 7

24/5 + y = 7

y = 7 - 24/5

y = 35/5 - 24/5

y = 11/5

Answer 2

x = 1 ; y = 3

Explanation:

`4x + y = 7 \\ y = 7 - 4x`

Now we know the value of y is 7 - 4x we plug this value to the second equation with y, So,

`3x + 2(7 - 4x) = 9 \\ 3x + (14 - 8x) = 9 \\ - 5x = 9 - 14 \\ - 5x = - 5 \\ x = ( - 5)/( - 5) \\ x = 1`

Now to find the value of y we use the first equation

`y = 7 - 4x \\ y = 7 - 4(1) \\ y = 7 - 4 \\ y = 3`

Hope this helps you :)