Question

[Minh Tú Nguyễn]

112 - (x+4)=1339:13
468+85xX=2508
Xx2,5=2,5x4
x-270:45=120
575-(6xX+70=445
x-105:21=15
3200:(405-x)=8
43575-75xX=42450
8,75xX+1,25xX=20

Answer 1

[GV Nguyễn Trần Thành Đạt]

112 - (x+4)=1339:13

112 - (x+4)=103

x+4= 112-103

x+4=9

x=9-4

x=5

_________
468+85xX=2508

85 x X = 2508 - 468 

85 x X = 2040

X= 2040 : 85

X=24

____
Xx2,5=2,5x4

X x 2,5 = 10

X= 10:2,5

X=4

________

x-270:45=120

X - 6 = 120

X= 120+6

X=126

Answer 2

[GV Nguyễn Trần Thành Đạt]

575-(6xX)+70=445

(6 x X) + 70 = 575 - 445

(6 x X) + 70= 130

6 x X = 130 - 70

6 x X = 60

X= 60:6

X=10

______
x-105:21=15

X - 5 = 15

X= 15+5

X=20

______
3200:(405-x)=8

405 - x = 3200 : 8

405 - x = 400

x= 405 - 400

x= 5

_______

43575-75xX=42450

75 x X = 43575 - 42450

75 x X = 1125

X= 1125:75

X= 15

______
8,75xX+1,25xX=20

(8,75 + 1,25) x  X = 20

10 x X = 20

X=20:10

X=2