Răspuns:
5.
a) 3×x=81
x=81÷3
x=27
b)(-11)×y=121
y=121÷(-11)
y= -11
c)(-35)×z=-210
z=(-210)÷(-35)
z=6
6.
a)x÷(-8)=20
x=20×(-8)
x=-160
b)y:38=10
y=10×38
y=380
c)z÷(-19)=-18
z=-18×(-19)
z=342
7.
a)3x+72=0
3x=0-72
3x=-72
x=-72÷3
x=-24
b)-8y+800=0
-8y=0-800
-8y=-800
y=-800÷(-8)
y=100
c)22z+440=0
22z=0-440
22z=-440
z=-440÷22
z=-20
