Given the function f(x) = 2x^2 + 3.When f(x) = 53 find both values of x

Sub in f(x)=53 into equation. So you have 53=2x^2+3, deduct 3 from both sides to get 50=2x^2 and then divide each side by 2 to get 25=x^2 and finally square root both sides to get x=5 or x=-5.