Question

Solve: x2 - 20x + 36 = 0
A. {6, -6}
B. {2, 18}
C. {-4, -9}
D. no solution

Answer 1

you can use quadratic formula to solve it
\[x=(-b \pm \sqrt{b^2 - 4ac}) /(2a)\]

Answer 2

B

Answer 3

or you can solve it by factoring the expression on the left hand side

Answer 4

x2-20x+36
use a method-----
x = (-b+- sqrt(b^2- 4ac))/(2a)
a=1
b=-20
c=36
so sqrt((-20)2 - 4(1)(36)) = 16
so x=(20+-16)/2=(36)/2 or (4)/2 = (18, 2)
Ans-B

Answer 5

Alternatively----
x^2 - 18x - 2x + 36 = x(x-18) - 2(x-18) = (x-2)(x-18)=0
So either x-2=0 or x-18=0
Thus, x=2 or x=18
Ans x=(2, 18)
B