Question

Solve the system of linear equations by graphing.

y = –y equals negative StartFraction 5 over 2 EndFraction minus 7.x – 7

x + 2y = 4

What is the solution to the system of linear equations?

(–4.5, 4.25)
(–1.7, –2.8)
(0, –7)
(3, 0.5)

Answer 1

Interpreting the first equation as y = −(5/2)x − 7, substitute into x + 2y = 4:

x + 2(−(5/2)x − 7) = 4
x − 5x − 14 = 4
−4x = 18 → x = −4.5

y = −(5/2)(−4.5) − 7 = 11.25 − 7 = 4.25

Solution: (−4.5, 4.25).