4x^2-25-(2x-5)(2x+7)=0
<=> 4x^2 - 25 - (4x^2 + 14x - 10x - 35) = 0
<=> 4x^2 - 25 - 4x^2 - 14x + 10x + 35 = 0
<=> -4x + 10 = 0
<=> x = -10/-4
<=> x = 5/2
4x^2-25-(2x-5)(2x+7)=0
<=> 4x^2 - 25 - (4x^2 + 14x - 10x - 35) = 0
<=> 4x^2 - 25 - 4x^2 - 14x + 10x + 35 = 0
<=> -4x + 10 = 0
<=> x = -10/-4
<=> x = 5/2