Question

Solve by using the perfect squares method.

x2 + 8x + 16 = 0

A.
2

B.
4

C.
–4

D.
–2

Answer 1

how do i do this?

Answer 2

first of all you look at x^2 and 16 are they perfect squares?

Answer 3

yea

Answer 4

ok so since they are then you look and see if 2 times the coefficient of x and the square root of 16 = +8 which is your middle term

so coefficient of x = 1 and squareroot of 16 = 4 so does 4*1*2 = 8?

Answer 5

where does the 2 come from?

Answer 6

when you have a perfect square it has to follow this

\[(x+a)^2\]
\[(x+a)(x+a)\]
\[x^2+xa+xa+a^2\]
\[x^2+2ax+a^2\]

Answer 7

okay

Answer 8

so that is where the 2 comes into play