Sonia graphs the equations y = –x2 + 4x and y = x – 4 to solve the equation –x2 + 4x = x – 4. Her graph is shown below.

C.–1 and 4

Step-by-step explanation:

Solving the equations  y = –x² + 4x and y = x – 4

–x² + 4x = x – 4

x² - 4x + x = 4

x² - 3x = 4

x² - 3x + (3/2)² = 4 +  (3/2)²

(x - 3/2)² = 4 +  9/4

             = 6.25

x - 3/2 = √6.25                      or  x - 3/2 = -√6.25

x = 2.5 + 1.5                                        x = -2.5 + 1.5

= 4                                                        = -1

answer: they are supplementary angles

step-by-step explanation: 161+19=180. supplementary angles equal 180 degrees