71-50:[5+3.(57-6.7)]

 =71-50:[5+3.15]

= 71-50:50

=70

71-50:[5+3.(57-6.7)]

 =71-50:[5+3.15]

= 71-50:50

=70

what are you doing?

a) 0

b) \(\dfrac{149}{132}\)

trình bày thì bn tự làm nhé

tưởng câu a=0 chứ

a)

70-5(x-3)=45

5(x-3)=70-45

5(x-3)=25

x-3=25:5

x-3=5

x=8

b)

10+2x=4⁵÷4³

10+2x=16

2x=16-10

2x=6

x=3

c)

7.(x-14)+35=25+279÷9

7.(x-14)+35=56

7.(x-14) = 56-35

7.(x-14) = 21

x-14=3

x=17

d)

324-(318-x)=115

318-x=324-115

318-x=209

x=109