Question

Solve each system using substitution.

1. 4x= 3y-2 ; 18= 3x+y​

Answer 1

x = 4, y = 6

Explanation:

Substituting y into 1:

4x= 3y-2 -----1

18= 3x+y -----2

Isolate the y in 2.

y = 18-3x -----3

Substitute 3 into 1.

4x= 3(18-3x)-2

Evaluate.

4x = 54-9x-2

Keep like terms together.

4x+9x = 54-2

Simplify.

13x = 52

Find x.

x = 52 ÷ 13

= 4

Substitute x into 3.

y = 18-3(4)

Evaluate.

y = 18-12

Find y.

y = 6

Answer 2

y = 6

Explanation:

so since you have 2 variables, you need to find a substitution for one of them.

let's do that for y

let y = something in the second equation.

y = 18 - 3x

then plug this into the first equation

4x = 3(18 - 3x) - 2

4x = 54 - 9x -2

4x = 52 - 9x

13x = 52

x = 4

now you have x, plug it into any of the equations to find y.

4(4) = 3y - 2

16 = 3y - 2

18 = 3y

y = 6