Question 896827

x^5 − 8x^4 + 15x^3 + 20x^2 − 76x + 48 = 0



48/6=8 so we can eliminate  12, 24 and 48 want to check factors of 8 that is  8,4,-1, -2
just plug them in and see if they work
(4)^5 − 8(4)^4 + 15(4)^3 + 20(4)^2 − 76(4) + 48 = 0 true
(-2)^5 − 8(-2)^4 + 15(-2)^3 + 20(-2)^2 − 76(-2) + 48 = 0 true
(8)^5 − 8(8)^4 + 15(8)^3 + 20(8)^2 − 76(8) + 48 = 0 false
other roots are x=-2 and x=4