Y = x² + 7x - 4
y = -x - 4
x² + 7x - 4 = -x - 4
+ x + x
x² + 8x - 4 = -4
+ 4 + 4
x² + 8x = 0
x(x) + x(8) = 0
x(x + 8) = 0
x = 0 or x + 8 = 0
- 8 - 8
x = -8
y = -x - 4
y = -0 - 4
y = 0 - 4
y = -4
(x, y) = (0, -4)
or
y = -x - 4
y = -(-8) - 4
y = 8 - 4
y = 4
(x, y) = (-8, 4)
The solutions are (0, -4) and (8, -4).
Answer:
Hey there!
You can think of the rate of change as the slope of a quadratic function- here we see that it is 9/-3, or - 3.
Let me know if this helps :)
The sign only changes when divided or multiplied by a negative number.
