Question

Orapns of Polynomial Functions

Question 10 of 10
Which of the following is an x-intercept of the function, f(x) = x2 -5x2 - 8x +48
?
A. -4
o
B. 4
C. -2
O
D. 2

Answer 1

Option B: 4

Explanation:

From the image, the correct function is;

f(x) = x³ -5x² - 8x + 48

Now, the x-intercept occurs when y = 0.

Thus;

x³ - 5x² - 8x + 48 = 0

So we are looking for values of x that will make y = 0.

Let's try the options;

Let's try x = -4;

(-4)³ - 5(-4)² - 8(-4) + 48 = -64 - 80 + 32 + 48 = -64 ≠ 0

So, x = -4 is not an x - intercept

Let's try x = 4;

(4)³ - 5(4)² - 8(4) + 48 = 64 - 80 - 32 + 48 = 0

So,x = 4 is an x-intercept

Let's try x = - 2;

(-2)³ - 5(-2)² - 8(-2) + 48 = -8 - 20 + 16 + 48 = 36 ≠ 0.

So, x = -2 is not an x-intercept.

Let's try x = 2;

(2)³ - 5(2)² - 8(2) + 48 = 8 - 20 - 16 + 48 = 20 ≠ 0

So, x = 2 is not an x-intercept