Question

Giảng hộ em mình nhé mình ko có thời gian giảng cho em giúp mình!!

1).  (1+x)+(2+x)+(3+x)+(4+x)+(7+x)+......+(22+x)=77

2).  102:x-7,5:x=27

Answer 1

1)(1+x)+(2+x)+(3+x)+.....+(22+x)=77

=>1+x+2+x+.....+22+x=77

=>22.x+(1+2+3+.....+21+22)=77

=>22.x+253=77

=>22x=77-253

=>22x=-176

=>x=-8

Answer 2

đề sai 

Answer 3

1) \(\left(1+x\right)+\left(2+x\right)+\left(3+x\right)+....+\left(22+x\right)=77\)(22 cặp)

\(\Rightarrow1+x+2+x+3+x+......+22+x=77\)

\(\Rightarrow\left(1+2+3+.....+22\right)+\left(x+x+x+....+x\right)=77\)(22 số x)

\(\Rightarrow\left[\left(22+1\right).22:2\right]+22x=77\)

\(\Rightarrow253+22x=77\Rightarrow22x=77-253\Rightarrow22x=-176\Rightarrow x=-8\)

Answer 4

2)\(102:x-7,5:x=27\) \(\Leftrightarrow102.\frac{1}{x}-7,5.\frac{1}{x}=27\)

\(\Rightarrow\frac{1}{x}\left(102-7,5\right)=27\)\(\Rightarrow\frac{1}{x}.94,5=27\)\(\Rightarrow\frac{1}{x}=27:94,5\Rightarrow\frac{1}{x}=\frac{2}{7}\Rightarrow x=1:\frac{2}{7}\Rightarrow x=\frac{7}{2}=3,5\)