:①(2a+5b)²
=(2a)²+2×2a×5b+(5b)²
=4a²+20ab+25b²
②(4x-3y)²
=(4x)²-2×4x×3y+(3y)²
=16x²-24xy+9y²
③(-2m-1)²
=(2m+1)²
=4m²+4m+1
④(1.5a-2/3b)²
=(1.5a)²-2×1.5a×2b/3+(2b/3)²
=2.25a²-2ab+4b²/9
:①(2a+5b)²
=(2a)²+2×2a×5b+(5b)²
=4a²+20ab+25b²
②(4x-3y)²
=(4x)²-2×4x×3y+(3y)²
=16x²-24xy+9y²
③(-2m-1)²
=(2m+1)²
=4m²+4m+1
④(1.5a-2/3b)²
=(1.5a)²-2×1.5a×2b/3+(2b/3)²
=2.25a²-2ab+4b²/9