Bài 5 trang 177 sgk toán 5 tiết 171 luyện tập chung


Tìm x: 8,75 x x + 1,25 x x = 20

Tìm x: 

\(8,75 \times x + 1,25 \times x = 20\)

Bài giải:

\(\eqalign{
& 8,75 \times x + 1,25 \times x = 20 \cr
& \left( {8,75 + 1,25} \right) \times x\,\,\,\, = 20 \cr
& \,\,\,\,\,\,\,10 \times x\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 20 \cr
& \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,x\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 20:10 \cr
& \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,x\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = \,\,\,\,\,2 \cr} \)