How do you 3x^3 - x^2-39 + 30 ?

Question

oh yea, I have forgot a varaible

3x^3 - x^2 -39x + 30

oops, how do you factor?

Answer 1

♠ y(x)=3x^3 - x^2 -39x +30=0; first analyze! y’=9x^2 –2x –39 =0, hence x=(1+s*r)/9, s=-1 or +1, r= sqrt(1+9*39) = 18.76166, so x1=-1,973518115 and x2= 2,195740338 are local extremes; then y(x1)=80 and y(x2)=-28.7 have different signs, that means a root x3 is in between of extremes x1 ♣ the situation clear let’s try to group:
y(x)=(3x –10)x^2 +3(3x –10)x –3(3x –10) = (3x-10)(x^2 +3x-3) =
=(3x-10) (x+1.5+0.5*21^0.5) (x+1.5-0.5*21^0.5);
♦ then x5=10/3; x4=(-3-sqrt21)/2; x3=(-3+sqrt21)/2;

Answer 2

a million. (3x3 - x2 - 5) - (x + 2) = (9-x2 - 5) - (x+2) = (4 - x2) - (x+2) = 4 - x2 - x - 2 (as - & + will become -) = x2 - x - 2 = Take x & a million as person-friendly, = x (x-a million) - a million (x+2) = (x-a million) (x+2) So, x= a million & x = -2 2. (4x4 + 3x + x2) - (x2 - 6 + 3x3) = (sixteen + 3x + x2) - ( x2 - 6 + 9) = (x2 +3x+ sixteen) - (x2-3) = x2 +3x + sixteen - x2 -3 = 3x + 13 = > x = 13/3 3. (5x - 6) - (3x3 - 2x2) = 5x - 6 - 9 -4 = 5x - 19 => 5x =19 => x = 19/5 4. (x - 3x4 + 2x2) - (-x3 + 4x6) = (x - 12 + 4) - (-x3 + 4x6) = (x - 8) - (-x3 + 24) = (x - 8 -x3 - 24) = x3 - x - 32 5.

Answer 3

what are you trying to find...are you simplifying...if so just add -39 + 30

Answer 4

I think you have made a mistake in typing of question. Please check.

Answer 5

check your question again!