(x+1)(x+3)-15
=x²+4x+3-15
=x²+4x-12
=(x-2)(x+6)
9(2x+3)²-4(2x-5)²
=9(4x²+12x+9)-4(4x²-20x+25)
=36x²+108x+81-16x²+80x-100
=20x&...
(x+1)(x+3)-15
=x²+4x+3-15
=x²+4x-12
=(x-2)(x+6)
9(2x+3)²-4(2x-5)²
=9(4x²+12x+9)-4(4x²-20x+25)
=36x²+108x+81-16x²+80x-100
=20x&...