If f(x)= x2 + 7; Find x if f(x)= 23
Mathematics · High School · Thu Feb 04 2021
Answered on
Given:
f(x) = x^2 + 7
Find x if f(x) = 23
Solution:
Substitute the value of 23 to f(x) then solve for x.
f(x) = x^2 + 7
23 = x^2 + 7
Transpose 7 to the other side of the equation, hence we must take note that in transposing a number, the sign changes.
x^2 = 23 - 7
x^2 = 16
Take the square root of both sides of the equation. This can be done either by enclosing both sides with a square root sign, or raising both sides to ½.
(x^2)^½ = (16)^½
x = 4
Final answer:
x = 4