Question

Tìm x :

120 + 80 = 500 - x

100 + 100 = 400 - x

Answer 1

  \(120\)\(+\)\(80\)\(=\)\(500\)\(-\)\(x\)                     \(100\)\(+\)\(100\)\(=\)\(400\)\(-\)\(x\)

            \(200\)        \(=\)\(500\)\(-\)\(x\)                              \(200\)           \(=\)\(400\)\(-\)\(x\)

\(500\)\(-\)\(200\)\(=\)\(x\)                                         \(400\)\(-\)\(200\)\(=\)         \(x\)

           \(300\)          \(=\) \(x\)                                                  \(200\)           \(=\)        \(x\)

Answer 2

120 + 80 = 500 - x

200 = 500 - x

x = 300

100 + 100 = 400 - x

200 = 400 - x

x = 200

Answer 3

120 + 80 = 500 - x

100 + 100 = 400 - x

Ta có : 

120 + 80 = 500 - x

=> 500 - x = 200

=> x = 300

Lại có : 

100+100=400-x

=> 400-x = 200

=> x = 200

Answer 4

120 + 80 = 500 - x

<=> 500 - x = 200

x = 500 - 200

x = 300

100 + 100 = 400 - x

<=> 400 - x = 200

x = 400 - 200

x = 200

Answer 5

120 + 80 = 500 - x

500 - x = 200

x = 500 - 200

x = 300

Vậy x = 300

100 + 100 = 400 - x

400 - x = 200

x = 400 - 200

x = 200

Vậy x = 200

Answer 6

120+80=500-x

500-x=200

=>x=500-200=300

100+100=400-x

400-x=200

=>x=400-200=200

Answer 7

\(120+80=500-x\)

\(200=500-x\)

\(x=500-200\)

\(x=300\)

\(100+100=400-x\)

\(200=400-x\)

\(x=400-200\)

\(x=200\)

Answer 8

x=300

x=200

Answer 9

120 + 80 = 500 - x

200 = 500 - x

500 - 200 = x

300 = x

100 + 100 = 400 - x

200 = 400 - x

400 - 200 = x

200 = x