2x cubed -4x sq.+ 8x -3 x=-2
f(x) = 2x^3 - 4x^2 + 8x - 3
so, if x = -2, just replace all the x's with (-2)'s:
f(-2) = 2(-2)^3 - 4(-2)^2 + 8(-2) - 3
= 2(-8) - 4(4) + 8(-2) - 3
= -16 - 16 - 16 - 3
= -51
Note how much clearer using ^ for powers is than all that wordy mumbo-jumbo.
2 x^3 - 4 x^2 + 5 x + 2 = 0 ??????
I suspect a typo and you do not say what you want. I assume roots.
using
http://www.mathportal.org/calculators/polynomials-solvers/polynomial-roots-calculator.php
x1=−0.31075
x2=1.15537+1.37229∗i
x3=1.15537−1.37229∗i
I did not understand your question.
since no question was posed, just a murky and cryptic expression.
Next time, SHAELYNNN, try to be it clear just what it is you need help with. We tend to ignore postings where we have to figure out the question as well as the answer!
To find the value of the expression 2x^3 - 4x^2 + 8x - 3 when x = -2, you need to substitute -2 for x in the expression and perform the calculations. Here's how you can do it step by step:
Step 1: Start with the expression 2x^3 - 4x^2 + 8x - 3.
Step 2: Replace every occurrence of x with -2.
2(-2)^3 - 4(-2)^2 + 8(-2) - 3
Step 3: Simplify the expression after substituting -2 for x.
2(-8) - 4(4) - 16 - 3
-16 - 16 - 16 - 3
-32 - 19
Step 4: Perform the addition and subtraction operations.
-51
So, when x = -2, the expression 2x^3 - 4x^2 + 8x - 3 is equal to -51.