Question

What value of c would complete the square for the following trinomials?

Answer 1

`x^2+6x+c\colon`

To find the value of c that will make the given expression a perfect square, we simply;

Step 1: Take the coefficient of x : that is, 6

Step 2: Divide the coefficient obtained in step 1 by 2: That is, 6/2 = 3

Step 3: Square the result in step 2: That is, 3^2 = 9

Hence, c = 9

The value of c in the first expression is 9.

Second Expression:

`x^2-10x+c`

Step 1: 10 ( Do not bother yourself with the negative sign, just pick the number 10)

Step 2: 10/2 = 5

Step 3: 5^2 = 25

so, c = 25

Third expression:

`x^2+32x+c`

Step 1: 32

Step 2: 32/2 = 16

Step 3: 16^2 = 256

So, c = 256

Fourth expression:

`x^2-12x+c`

Step 1: 12

Step 2: 12/2 = 6

Step 3: 6^2 = 36

So, c = 36

Last expression:

`x^2+8x+c`

Step 1: 8

Step 2: 8/2 = 4

Step 3: 4^2 = 16

so, c = 16