Question

What number must you add to complete the square? x^2 + 4x = 15

Answer 1

What is x coefficient here??

Answer 2

Add 4 both the sides..

Answer 3

What is (x+2)^2?

Answer 4

add 4 on both sides.. x2 + 4x +4 =15 + 4
x2 + 4x +4 = 19
(x+2)2 = (squareroot 19) 2

Answer 5

so 4 ?

Answer 6

yaaah

Answer 7

thankks !

Answer 8

got it??

Answer 9

Completing the square ( step by step )

Step 1 : Use b/2 = 2 where b = Coefficient of x ; in this case b=4 so b/2 = 2
Step 2 : Add (b/2)^2 to both sides in this case (B/2)^2 2^2 =4

X^2 + 4x = 15

X^2 + 4x + 4 = 15 +4 = 19 ( left side a a perfect square )

( X + 2) ) ^2 =19

From your question the response should be (b/2)^2 = 4