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Solve 2x3 + x2 - 15x completely by factoring.

User Hubris
by
5.7k points

2 Answers

5 votes
0, -3, 5/2 would be your answers
User MarkDBlackwell
by
6.5k points
6 votes
Answer:
The solutions are 0 , 5/2 and -3

Step-by-step explanation:
The given expression is:
2x³ + x² - 15x
We can note that we can take x as a common factor from all terms. This will give us:
x(2x²+x-15)

Now, the expression 2x² + x - 15 is a second degree polynomial that can be factored using the quadratic formula shown in the attached image.
In the given expression:
a = 2
b = 1
c = -15
Substituting with the values of a, b and c in the formula, we would find that
2x² + x - 15 can be factored as (2x-5)(x+3)

Based on the above, the factored form of the given expression is:
x(2x-5)(x+3)

Now, to find the solutions means to find the values of x that would make the expression equal to zero.
This means that:
x(2x-5)(x+3) = 0
either x = 0
or 2x-5=0 .............> 2x = 5 ...........> x = 5/2
or x+3=0 ............> x = -3

Based on the above, the solutions of the system are:
0 , 5/2 and -3

Hope this helps :)
Solve 2x3 + x2 - 15x completely by factoring.-example-1
User McPeppr
by
5.5k points