(x+3)(x-5)=x×x-x×5+3×x-3×5=x²-5x+3x-15=x²-2x-15 (x+2)(x+5)=x×x+x×5+2×x+2×5=x²+5x+2x+10=x²+7x+10 (2m+3)(m-4)=2m×m-2m×4+3×m-3×4=2m²-8m+3m-12=2m²-5m-12 (x+1)(x+2)=x×x+x×2+1×x+1×2=x²+2x+x+2=x²+3x+2
