1).a. (2x+3)²
=(2x)²+2×(2x)×3+3²
=4x²+12x+9
b. (x-5)²
=x²-2×x×5+5²
=x²-10x+25
c. D=(2x+3)-2(x-5)
=(2x+3)-2x+10
=2x+3-2x+10
=13
2). A=(8-5x)²
=8²-2×8×5x+(5x)²
=64-80x+25x²
=25x²-80x+64
B=4x(3x-1)-(3x-7)(5-3x)
=12x²-4x-(15x-9x²-35+21x)
=12x²-4x-15x+9x²+35-21x
=21x²-40x+35