How do you solve #10x ^ { 3} - 1x ^ { 2} - 2x = 0#?

1 Answer
Oct 15, 2017

See a solution process below:

Explanation:

First, factor an #x# out of each term on the left side of the equation:

#10x^3 - 1x^2 - 2x = 0# becomes:

#x(10x^2 - 1x - 2) = 0#

Next, factor the quadratic on the left side of the equation giving:

#x(5x + 2)(2x - 1) = 0#

Now, solve each term on the left side of the equation for #0#:

Solution 1:

#x = 0#

Solution 2:

#5x + 2 = 0#

#5x + 2 - color(red)(2) = 0 - color(red)(2)#

#5x + 0 = -2#

#5x = -2#

#(5x)/color(red)(5) = -2/color(red)(5)#

#(color(red)(cancel(color(black)(5)))x)/cancel(color(red)(5)) = -2/5#

#x = -2/5#

Solution 3:

#2x - 1 = 0#

#2x - 1 + color(red)(1) = 0 + color(red)(1)#

#2x - 0 = 1#

#2x = 1#

#(2x)/color(red)(2) = 1/color(red)(2)#

#(color(red)(cancel(color(black)(2)))x)/cancel(color(red)(2)) = 1/2#

#x = 1/2#

The solutions are:

#x = 0# and #x = -2/5# and #x = 1/2#