factorize the following polynomials using synthetic division method 2x3-7x2-10x+24
Answers
we have to factorize the polynomial 2x³ - 7x² - 10x + 24 using synthetic division method.
solution : first write it in coefficient form,
2 , -7 , -10 , 24
checking for x = 1
1 | 2, -7, -10, 24
1 -6 -16
................................
2 -6 -16 8 [ not zero ] so x = 1 is not zero of given polynomial.
let's check for x = 2
2 | 2, -7, -10, 24
4. -6 -8
...............................
2 -3 -4 16 [ not zero ]
again, check for x = -2
-2 |2, -7, -10, 24
-4 22 -24
................................
2 -11 12 0 [ zero so x = -2 is zero of given polynomial and (2x² - 11x + 12) is another factor of given polynomial ]
so, factorisation is (x + 2)(2x² - 11x + 12)
you can also apply, synthetic division method for 2x² - 11x + 12
take x = 4, as f(x) = 2x² - 11x + 12 = 0 at x = 4
4 |2 , - 11, 12
8. -12
.......................
2 -3 0
so 2x² - 11x + 12 = (x + 4)(2x - 3)
Therefore factorisation of 2x³ -7x² - 10x + 24 = (x + 2)(x + 4)(2x - 3)
Step-by-step explanation:
First we need to do trial and error method
put x=-2
= 2(-2)^3-7(-2)^2-10(-2)+24
= 2(-8)-7(4)+20+24
= -16-28+20+24
= 0
So, x+2 is a factor
Now, use synthetic division method
coefficients of the polynomial are
2,-7,-10,24
x=-2 | 2. -7. -10. 24
+ | 0. -4. 22. -24. ( -2× the result)
2. -11. 12. 0 -- Remainder
x^2. x. constant
Quotient = 2x^2-11x+12
Use Factorisation
2x^2-11x+12
= 2x^2-8x-3x+12
= 2x(x-4)-3(x-4)
= (x-4)(2x-3)
Factors are (x+2)(x-4)(2x-3)