Asked by anon
                solve the following in the real number system
x^3 + 8x^2 + 10x - 15 = 0
Please help me!
            
            
        x^3 + 8x^2 + 10x - 15 = 0
Please help me!
Answers
                    Answered by
            Steve
            
    Since it is hard to factor a general cubic, look for easy roots. They will be among ±1,3,5,15
A little synthetic division shows that we have
(x+3)(x^2 + 5x - 5)
Now you can use the quadratic formula to get the other two roots:
(-5 ± 3√5)/2
    
A little synthetic division shows that we have
(x+3)(x^2 + 5x - 5)
Now you can use the quadratic formula to get the other two roots:
(-5 ± 3√5)/2
                    Answered by
            bobpursley
            
    by inspection, x=-3 is a solution.
-27+72-30-15=0
so, divide (x+3) into x^3+8x^2+10x-15 and get the quadratic. Then solve it with the quadratic equation.
I get x^2+5x-5 check that.
    
-27+72-30-15=0
so, divide (x+3) into x^3+8x^2+10x-15 and get the quadratic. Then solve it with the quadratic equation.
I get x^2+5x-5 check that.
                    Answered by
            sue
            
    Thank you I think I understand it better with Bob's answer. 
    
                                                    There are no AI answers yet. The ability to request AI answers is coming soon!
                                            
                Submit Your Answer
We prioritize human answers over AI answers.
If you are human, and you can answer this question, please submit your answer.