Question

Solve using substitution:2x + 3y - 4z = 9 4y – 6z = 16z = 2

Answer 1

x = -2, y = 7, z = 2

Step-by-step explanation

We are given a system of three equations:

2x + 3y - 4z = 9 ________(1)

4y - 6z = 16 ___________(2)

z = 2 ________________(3)

Since we have been given the value of z, from (3) we have that (2) becomes:

4y - 6(2) = 16

4y - 12 = 16

4y = 12 + 16 = 28

y = 28 / 4

y = 7

Put the values of y and z in (1):

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

2x + 21 - 8 = 9

2x + 13 = 9

Collect like terms:

2x = 9 - 13 = -4

x = -4 / 2

x = -2

So, x = -2 and y = 7 and z = 2