Use the completing the square method to solve the following. Round the solutions to the nearest tenth place.

1. n^{2 }= 18n + 40

2. 6x^{2} - 48 = -12x

Guest Mar 16, 2018

#1**+2 **

1) n^2 -18n = 40 take 1/2 of the 'n' coefficient, square it , then add it ro both the sides of the equation

n^2 -18n + 81 = 40 + 81

(n-9)^2 = 121 Now take sqrt of both sides

(n-9) = +- 11

n=20 or -2

ElectricPavlov
Mar 16, 2018

#2**+1 **

2) similar here

6x^2 +12x = 48

BUT you need to have x^2 coefficient = 1 so divide through by 6

x^2 + 2x = 8 Now 'complete the square' again

x^2 + 2x +1 = 8+1

(x+1)^2 = 9

x + 1 = +- 9

x =8 or -10

ElectricPavlov
Mar 16, 2018