1) (4а-1)(2а+3) = 4а×2а+4а×3-1×2а-1×3 = 8а^2+12а-2а-3 = 8а^2+10а-3
1) (4а-1)(2а+3)=8а²+12а-2а-3=8а²+10а-3
2)(3p-2q)(4p+5q)=12p²+15pq-8pq-10q²=12p²-7pq-10q²
3)(3b+2c)(5c-2b)=15bc-6b²+10c²-4bc=11bc−6b²+10c²
4)(-5x-2y)(3x-4y)= -15x²+20xy-6xy+8y²= -15x²+14xy+8y²
