6.
(-7xy)·3xy²+2x²(-5y³)-3x²y(-6y²)= -21x²y³-10x²y³+18x²y³=-13x²y³
Toti termenii au aceeasi parte literara, deci sunt asemenea. Atunci am facut suma algebrica (tinand seama de semne) a coeficientilor (cifrelor din fata literelor).
7.
(24a³b):(-6ab)=(-24:6)(a³b:ab)=-4a²
8.
(-3a³b/4):(-ab/2)=[(-3/4):(-1/2)]·(a³b:ab)=[(-3/4)·(-2/1)]·(a³b:ab)=6/4a²=3/2a²
9.
[(-√18)·a⁴b²]:[(-√2)/3]a²b=[(-9√2)·(-3/√2)]·(a⁴b²:a²b)=27a²b
