Question

Complete the square x^2+18x+_

Answer 1

Answer:

x²+8x+16

Step-by-step explanation:

To complete the square of the incomplete given equation means finding a constant that will complete the equation such that when it is factorised will give a perfect square.

To complete the equation x²+18x, we must find a constant to complete the quadratic equation. To get that constant, we will divide the coefficient of x by 2 and the square the resulting value as shown;

Step 1: First we get the coefficient of x in the equation which is 8.

Step 2: You will divide the coefficient of x by 2 to give;

8/2 = 4

Step 3: The square of the resulting value in the previous step is taken to get the constant needed i.e 4² which is 16

The complete form of the equation is therefore x²+8x+16

Factorizing the resulting equation will give (x+4)² which is a perfect square

Answer 2

Answer:

x^2 + 18x + 81 complete's the square.

Step-by-step explanation:

y = [x^2 + 18x + (18/2)^2 ] - (18/2)^2

y = [x^2 + 18x + 81] - 81

y = (x + 9)^2 - 81 This is just to make the completion of the square accurate.

You can't just add something to an expression. You have to balance it out.