Mathematics for IGCSE & O level - Functions (Section 2 - No. 15)
Which of the following equations correctly represents the inverse of the function f(x) = 5x - 5?
f^-1(x) = (x - 5)/5
f^-1(x) = (x + 5)/5
f^-1(x) = 5x + 5
f^-1(x) = -5x + 5
คำอธิบาย
To find the inverse, swap x and y and solve. x = 5y-5 => x+5=5y => y=(x+5)/5.