Question 46986
You brought the 25 back onto the side with the other parts, but when factoring, 20 * 5 is not 25 ... you looked for what added to 25 .. not what multiplied to get 25.

{{{ 4x^2+15x=25 }}}
{{{ 4x^2+15x-25=0 }}}
F: 4x * x = 4x^2
O: 4x * 5 = 20x
I: -5 * x = -5x
L: -5 * 5 = -25
{{{ (4x-5)(x+5)=0 }}}
{{{ 4x-5=0 }}} and {{{ x+5=0 }}}
add five and subtract five
{{{ 4x-5+5=0+5 }}} and {{{ x+5-5=0-5 }}}
{{{ 4x=5 }}} and {{{ x=-5 }}}
Divide by four on the first part
{{{ x=5/4 }}} and {{{ x=-5 }}}
x = {-5, 5/4}