`f):`
`(x × 4 + 13,4) × 2,5 = 50,5`
`= x × 4 + 13,4 = 50,5 : 2,5`
`= x × 4 + 13,4 = 20,2`
`= x × 4 = 20,2 - 13,4`
`= x × 4 = 6,8`
`x = 6,8 : 4`
`x = 1,7`
`g):`
`(1313)/(1212) : x = 1/(1 × 2) + 1/(2 × 3) + 1/(3 × 4) + 1/(4 × 5) + 1/(5 × 6)`
`= (1313)/(1212) : x = 1/2 + 1/6 + 1/12 + 1/20 + 1/30`
`= 13/12 : x = 1/2 + 1/6 + 1/12 + 1/20 + 1/30`
`= 13/12 : x = 2/3 + 1/12 + 1/20 + 1/30`
`= 13/12 : x = 3/4 + 1/20 + 1/30`
`= 13/12 : x = 4/5 + 1/30`
`= 13/12 : x = 5/6`
`x = 13/12 : 5/6`
`x = 13/12 × 6/5`
`x = 78/60`
`x = 13/10`
Cho mình xin hay nhất nha bạn!!!!
@Drew Mclntyre
