Which of the following are solutions to the equation below?
Check all that apply.
x²+x-20=0
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A. -5
B. 4
C. -20
D. -4
E. 5

x = 4 and x = -5

Step-by-step explanation:

Substitue the values of the equation into the quadratic formula, and solve to find x. Since x is a square number it will have 2 values; one positive and one negative.

A. -5         and     B. 4

Step-by-step explanation:

x²+x-20=0

This is a quadratic equation that, it can be solve through factorization method, formula or completing the square method. We will be using factorization method to solve.

First, we will find two numbers such that its product will give  -20  and its sum will give 1.

The number is 5 and -4.

The product of 5 and -4 will give -20   and the sum of 5 and -4 will give 1.

The next step is to replace x by 5x-4x in the quadratic equation.

x²+5x - 4x-20=0

(x²+5x) (- 4x-20)=0

In the first parenthesis, we will factor out x since it is common while in the second parenthesis, we will factor out -4 since it is common.

x(x+5) -4(x+ 5) = 0

(x+5)(x-4) = 0

x + 5 =0     or   x-4 =0

x = -5   or   x=4

x = -5 or 4

Therefore the solution is -5 or  4

-2

7 - 9 = -2

reversed:

-2 + 9 = 7