Question

One factor of the function f(x) = x ^ 3 - 8x ^ 2 + 17x - 10.5(x - 5) Describe how to find the x-intercepts and the y-intercept of the graph of f(x) without using technologyShow your work and include all intercepts in your answer.

Answer 1

Answer:

x-intercept(s):  (−1.9900717,  0)

y-intercept(s): (0, 52.5)

Step-by-step explanation:

To find the x-intercept, substitute in  $0$  for  $y$  and solve for  $x$. To find the y-intercept, substitute in  $0$ for $x$ and solve for $y$ .

$f(x)=y$

$(x)=x$

x-intercept

To find the x-intercept(s), substitute in  $0$  for  $y$  and solve for  $x$ .

$f(x) = x ^ 3 - 8x ^ 2 + 17x - 10.5(x - 5$

$=\bold{0}=x^3-8x^2+17x-10.5\left(x-5\right)$

$=0\cdot \:10=x^3\cdot \:10-8x^2\cdot \:10+17x\cdot \:10-10.5\left(x-5\right)\cdot \:10$

$=0=10x^3-80x^2+170x-105\left(x-5\right)$

$=0=10x^3-80x^2+65x+525$

$=10x^3-80x^2+65x+525=0$

$=10x^2-99.90071\dots x+263.80959\dots \approx \:0$

$\bold{x\approx \:-1.99007\dots}$

y-intercept

$f(x) = x ^ 3 - 8x ^ 2 + 17x - 10.5(x - 5$

$=y=\bold{0}^3-8(\bold{0})^2+17(\bold{0})-10.5\left(\bold{0}-5\right)$

$=y=0-8\cdot \:0+17\left(0\right)-10.5\left(0-5\right)$

$=y=0-8\cdot \:0+17\cdot \:0-10.5\left(0-5\right)$

$=y=0-0+0-\left(-52.5\right)$

$=0-0+0+52.5$

$\bold{y=52.5}$