Question

What number must you add to complete the square?

x2 + 14x = -7



A. 196
B. 49
C. 7
D. 14

Answer 1

\[x^2+bx+(b/2)^2=(x+b/2)^2\]

Answer 2

so add to both sides \[(b/2)^2 \]
can you guess what b should be?

Answer 3

14x ?

Answer 4

well b is just the 14
bx is 14x
but our formula calls for just b which is 14

Answer 5

so plug 14 into that (b/2)^2 thing to figure out your answer as to what to add to both sides in order to complete the square

Answer 6

oh 196

Answer 7

no

Answer 8

\[(\frac{14}{2})^2 \]
what is 14/2?

Answer 9

7 so the answer would be 49

Answer 10

\[(\frac{14}{2})^2=(7)^2=49\]
right