Answer:
8
Explanation:
x^2-4x=32
Subtract from both sides:
x^2-4x-32=32-32
Simplify the expression
x^2-4x-32=0
To find the coefficients, use the standard form of a quadratic equation:
ax^2+bx+c=0
x^2-4x-32=0
a coefficient =1
b coefficient =-4
c coefficient =-32
Find the factors which product equals to coefficient a multiplied by coefficient c:
a coefficient ∙ c coefficient = 1 ∙ -32 = -32
List the factors of -32:
1, 2, 4, 8, 16, 32
Because the product of coefficient a and coefficient c equals a negative number (-32) one factor needs to be positive and the other one negative.
From the list of factors, find a pair which sum equals to the b coefficient.
b coefficient = -4
This pair doesn't work.
1*-32=-32
2*-16=-32
2-16=-14
Found it - this pair does the trick:
4*-8=-32
4-8=-4
The product of 4 and -8 equals to coefficient a(1) multiplied by coefficient c (-32) and their sum equals to coefficient b (-4).