Question

2x²+5=13 How do you find the value of x?

Answer 1

Since 5 does not contain the variable to solve for, move it to the right-hand side of the equation by subtracting 5 from both sides.
2x^2=−5+13

Add −5 and 13 to get 8.
2x^2=8

Divide each term in the equation by 2.
x^2=4

Take the square root of both sides of the equation to eliminate the exponent on the left-hand side.
x=±√4

Rewrite 4 as 2^2
x=±√2^2

Pull terms out from under the radical.
x=±2

First, use the positive value of the ± to find the first solution.
x=2

Next, use the negative value of the ± to find the second solution.
x=−2


x=2,−2

Answer 2

2x²+5=13
subtract the 5 on both sides
2x²=8
divide by 2 on both sides
x²=4
put each side under the radical because of the exponent 2
√x²=√4
the radical cancels out the exponent 2; √4 = 2
x=2