настя5368 5a3+25ab-30a2
 (3x+y)(2x+1)-(3y+x)(6x+y)
(z-2)(z+2) + (3z-5)(2z+1) - z2+5z+1
x3−5x2+8xz+2+z2−x3+4x2−8xz-z²
−5a2b+8ab2+2+8a2b−15ab2−1

Uturna

Verified answer

1) 3b+7b = 3•b+7•b=10b
2) 5a+10a, если a=2. 5•a+10•a=a•(5+10)=a•15=2•15=30