To find the value of x for which f(g(x)) = 0, we first need to understand the given functions:
- f(x) = x2 – 2x
- g(x) = 6x + 4
Next, we can substitute g(x) into f(x):
f(g(x)) = f(6x + 4)
Now, we replace x in the function f(x) with g(x):
f(g(x)) = (6x + 4)2 - 2(6x + 4)
Expanding this expression:
f(g(x)) = (6x + 4)(6x + 4) - 2(6x + 4)
This further simplifies to:
f(g(x)) = 36x2 + 48x + 16 - 12x - 8
Combining like terms, we get:
f(g(x)) = 36x2 + 36x + 8
To find the value of x that makes this equal to zero, we set:
36x2 + 36x + 8 = 0
Now we can use the quadratic formula, which states that for any equation of the form ax2 + bx + c = 0, the solutions for x are given by:
x = (-b ± √(b2 - 4ac)) / (2a)
In our case, a = 36, b = 36, and c = 8. Plugging these values into the quadratic formula:
x = (-36 ± √(362 - 4 * 36 * 8)) / (2 * 36)
Calculating the discriminant:
362 - 4 * 36 * 8 = 1296 - 1152 = 144
Now compute the solutions:
x = (-36 ± √144) / 72
x = (-36 ± 12) / 72
Calculating both potential values:
x = (-36 + 12) / 72 = -24 / 72 = -1/3
x = (-36 - 12) / 72 = -48 / 72 = -2/3
Therefore, the solutions are:
- x = -1/3
- x = -2/3
These are the values of x for which f(g(x)) = 0.