Given f(x)=2x−4 and (f(x))2−6f(x)=−8 is satisfied by x1 or x2.
What is the value of x1⋅x2?
Explanation
Given the equation (f(x))2−6f(x)=−8 with f(x)=2x−4.
First, we rewrite the equation into the general form of a quadratic equation:
(f(x))2−6f(x)+8=0
Then we substitute f(x)=2x−4 into the equation:
(2x−4)2−6(2x−4)+8=0
Expand the quadratic form and simplify the equation:
(4x2−16x+16)−(12x−24)+8=0
4x2−16x−12x+16+24+8=0
4x2−28x+48=0
From the quadratic equation ax2+bx+c=0, the product of the roots (x1⋅x2) is given by the formula ac.
Given:
a=4 b=−28 c=48Then:
x1⋅x2=448=12
So, the value of x1⋅x2 is 12.