Hai bài ae giúp mình nha
Bai 1Tinh nhanh
a. $\frac{1}{15}$ .$\frac{7}{15}$+ $\frac{8}{15}$ .$\frac{1}{15}$- $\frac{16}{15}$
b) $\frac{-5}{11}$+ ($\frac{-6}{11}$ +1)
c. 6$\frac{4}{5}$ -(1$\frac{2}{3}$ +3$\frac{4}{5}$)
d. $\frac{5}{12}$ -$\frac{-7}{6}$
Baif 2
Tim x biet
a) $\frac{x}{12}$= $\frac{-1}{24}$- $\frac{1}{8}$
b) x + 25% x= -1,25
c) $\frac{2}{3}$+ $\frac{3}{4}$ :x=$\frac{-1}{6}$
d) $\frac{4}{7}$.x- $\frac{1}{2}=$ $\frac{1}{5}$
`1/(15).(7)/15+8/(15).(1)/15-16/15`
`=1/15.(7/15+8/15)-16/15`
`=1/(15).1-16/15`
`=1/15-16/15=-1`
`(-5)/11+((-6)/11+1)`
`=(-5)/11+5/11=0`
`6(4)/5-(1(2)/3+3(4)/5)`
`=34/5-(5/3+19/5)`
`=34/5-82/15=4/5`
`5/12-(-7)/6=19/12`
Đáp án:
Giải thích các bước giải:
c1:
a)-1/3
b)0
c)793/60
d)19/12
c2:
a)x/12=-1/6
mà -1/6=-2/12
suy ra x/12=-2/12
vậy x=2
b)x+1/4x=-1,25
5/4x=-1,25
x=-1,25:5/4
x=-1
c)3/4:x=-1/6-2/3
3/4x=-5/6
x=-5/6:3/4
x=-10/9
d)4/7x=1/5+1/2
4/7x=7/10
x=7/10:4/7
x=49/40
mình ko ghi đề nha bn