Respuesta :
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.
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