Since we want it in the form: (x - a)², let's first expand (x - a)² and then equate for the coefficients.
(x - a)² = x² - 2ax + a²
x² + 4x - 15 = x² - 2ax + a²
Now, let's focus on the middle term.
4x = -2ax
4 = -2a
a = -2
Thus, we know that a = -2
Then, we can say (x + 2)² = x² + 4x - 15
x² + 4x + 4 = x² + 4x - 15
Thus, 19 units are needed in order to complete the square to produce:
(x + 2)²
Percent change=change/original times 100
chane=28-23=5
oriiginal=28
percent change=5/28 times 100
0.178 times 100
17.8
about 18% change
First divide both sides by 5. Then you get the answer. -0 or 0 I'm not sure tho