How does this equal zero?! Please help! http://prntscr.com/aew1je

Question

mathmale · Answer

It's a conditional equation, true for two particular values of x.  Your task is to find those two values / solutions / roots.

mathmale · Answer

try dividing all three terms by 4.  Does this simplify the problem for you?

welshfella · Answer

this is  an equation and there are some values of x which satisfy it.
4x^2 - 100 = 0
add 100 to both sides
4x^2 - 100 + 100 = 100
4x^2 = 100
divide both sides by 4

x^2 = 25

ms-brains · Answer

And the square root of 25 is 5, so five would be the final answer...?

welshfella · Answer

no there is an other answer - there are 2 square roots of 25

mathmale · Answer

It would indeed be an answer, but there's another answer.  Find it.

ms-brains · Answer

Oh! 5, -5?

welshfella · Answer

correct

ms-brains · Answer

Thank you both! <3 I'd medal you both if I could. :P