Question

pleease help!!
What is the solution set of the following equation?

1/5x^2 = x - 4/5
{-1, -4}
{1, -4}
{1, 4}

Answer 1

You can substitute each solution set and see which one works.
It is faster than solving a cubic.

Answer 2

Don't know if you have a transcription error, the equation should read:
(1/5)x^2 = x - 4/5

Answer 3

so i substitute by putting the solution sets into the x place?

Answer 4

i tried that, but maybe i'm doing it wrong, because it doesnt seem to make sence

Answer 5

The equation should read :
(1/5)x^2 = x - 4/5
to make sense.

Answer 6

yeah, the equation already does read that, how do i substitute the solution sets?

Answer 7

For example, if the solution set is
{1,-4}
put x=1 and see if the equation balances. If so, try x=-4.
If both work, then you've found the solution set.
Example,
x=1:
(1/5)(1)^2 =(1) - 4/5
See if the equation is valid, and so on.

Answer 8

i keep getting .04=3.2

Answer 9

how is this cubic?

Answer 10

(1/5)x^2-x+4/5 = 0
x^2-5x+4 = 0
x^2 - 1x - 4x + 4 = 0
x(x-1)-4(x-1) = 0
(x-1)(x-4) = 0
x = 1 or x = 4