(x-4)(x^2+4x+16)-x(x+4)(x-4)=x^3-64-x(x^2-16)=x^3-64-x^3-16x=-16x-64=-16(x+4)
При x=-1,
-16(-1+4)=-16*3=-48
2) 2(х+21)+3(х-4)=5(х+6)
2х+42+3х+12=5х-30
2х+3х-5х=-30-42-12
x =-84
3) 5(3х+4)-6(3х-7)=23х
15х-20-18х+42=23х
15х-18х-23х=20-42
−56х=−22+56
х=34