Question

Ajutor!!!!!! Testul 2 ex 4,5

Answer 1

ex. 4
a) 12x89-12x39=12x(89-39)=12x50=600
b) 125x59+75x59-200x9=59x(125+75)-1800=
    59x200-1800=11800-1800=10000
c) 12xa+12xb-24=12x(a+b)-24

ex.5)
(13+8)(2x12-14)+(13+8)(5x12+10)=
21(24-14)+21(60+10)=
21(10+70)=21x80=1680
    

Answer 2

ex.4
a)
12×89-12×39=
=12×(89-39)
=12×50
=600
b)
125×59+75×59-200×9=
=59×(125+75)-1800
=59×200-1800
=11800-1800
=10000
c)
12×a+12×b-24=
=12×(a+b)-24
=12×(a+b)=24
a+b=24÷12
a+b=2

ex.5
(13+8)(2×12-14)+(13+8)(5×12+10)=
=21(24-14)+21(60+10)
=21×10+21×70
=210+1470
=1680