Question

Solve the system of equations using the substitution method.

S 4x + 5y=7
ly=3x +9
Enter your answers in the boxes.
2
X=
y=

Answer 1

x = -2.

y = 3.

Explanation:

If y = 3x + 9

Substitute this value for y in the first equation.

4x + 5(3x + 9) = 7

4x + 15x + 45 = 7

19x = 7 - 45

19x = -38

x = -38/19

x = -2.

with this value of x, substitute -2 in the second equation

y = 3(-2) + 9

y = -6+9

y = 3.

check if your values are all correct

4(-2) + 5(3) = 7

-8 + 15 = 15 - 8 = 7

Correct!