Solve for the x (x - 8)(X + 4) = -42?

Question

Solve for the x

Answer 1

X (X^2 - 4X - 32) = -42
X^3 - 4X^2 - 32X + 42 = 0
Do the rest your self

Answer 2

First you have to expand the equation:
x (x - 8) (x + 4) = -42
x (x^2 - 8x + 4x - 32) = -42
x (x^2 - 4x - 32) = -42
x^3 - 4x^2 - 32x = -42

Set the equation equal to zero:
x^3 - 4x^2 - 32x +42 = 0

Now plot using your graphing calculator:
The zeros are:
-4.70302
1.18841
7.51461

Answer 3

1. parenthesis
x((X x X) + (4 x X) - (8 x X) + (4 x -8)=-42
x(x^2+4x-8x-32)=-42
x(x^2+-4x-32)=-42
x^3-4x^2-32x=-42
2. get everything on one side
x^3-4x^2-32x+42=-42+42
x^3-4x^2-32x+42=0
3. use your graphing calcuator and find the zeros
1.graph it
2. 2nd trace(calc)
3. left bound means left of zero, right bound means right of the zero
4.find each zero

Answer 4

(x^2-8x)(x+4)= -42 now you must FOIL it together...mutliply the first 2, the outside 2, the inside 2, then the last 2

x^2*x+(x^2+4)+(-8x*x)+(-8x+4)=-42
so x^2+x=x^3..remember when multiplying, we add the exponents
x^3+(x^2+4)+-8x^2-32x=-42combine like terms
x^3-7x^2+4-32x=-42 bring -42 across, change its sign, set the whole thing equal to zero
x^3=7x^2-32x+46=0 pair up
(x^3-7x^2)(-32x+46)=0 factor
x^2(x-7)2(-16x+23)=0
(x^2+2)(x+9)(-16x+23)=0

x^2+2=0 x^2=-2 impossible

x-7=0 x=7

-16x+23=0
-16x=23
x=-23/16

answers x=7 and x=-23/16

Answer 5

(8X-10)/((X-4)