5(2x+5)²+（3x-4）(-3x-4)
=5（4x²+20x+25)+(-4+3x)(-4-3x)
=20x²+100x+125+16-9x²
=11x²+100x+1415(2x+5)²化简一下是啥=5((2x)^2+2*(2x)*5+5^2)=5(4x^2+20x+25)=20x^2+100x+125