Answer:
2
Step-by-step explanation:
Given the function
f(x) = x^3 − x + 4 in the interval [1,2]
We are to find the value of x for which f(x) = 7
Substitute f(x) = 7 into the expression as shown!
f(x) = x^3 − x + 4
7 = x^3 − x + 4
x^3 − x + 4 -7 = 0
x^3 − x - 3= 0
x^3 -x = 3
x(x²-1) = 3
x²-1 = 3 and x = 3
x² = 3+1
x² = 4
x = ±√4
x = ±2
Since x lies within the interval, [1,2] hence the value of x is 2
