Question

What are the solutions of x^2-4=21 ? Use the quadratic formula.

Answer 1

To find the solutions of the equation x^2 - 4 = 21 using the quadratic formula, we first need to rewrite the equation in standard form:

x^2 - 4 - 21 = 0
x^2 - 25 = 0

Now we can identify the coefficients of the equation:

a = 1
b = 0
c = -25

Now we can plug these values into the quadratic formula:

x = (-b ± √(b^2 - 4ac)) / 2a

x = (0 ± √(0^2 - 4*1*-25)) / 2*1
x = (± √(0 + 100)) / 2
x = ± √100 / 2
x = ± 10 / 2
x = ± 5

Therefore, the solutions to the equation x^2 - 4 = 21 are x = 5 and x = -5.