Краткий ответ:
- \(x=\frac14\)
- \(t=\frac18\)
- \(b=\frac15\)
- \(y=\frac14\)
- \(a=\frac18\)
- \(p=0\)
- \(b=\frac16\)
- \(c=\frac16\)
Решение
1)
\[
x+\frac23=\frac34+\frac16
\]
\[
x=\frac34+\frac16-\frac23
=\frac9{12}+\frac2{12}-\frac8{12}
=\frac3{12}=\frac14
\]
2)
\[
\left(\frac38-t\right)+\frac12=\frac34
\]
\[
\frac38+\frac48-t=\frac68
\]
\[
\frac78-t=\frac68,\qquad t=\frac18
\]
3)
\[
\frac65-\left(b+\frac23\right)=\frac13
\]
Перенесём скобки:
\[
b+\frac23=\frac65-\frac13=\frac{18}{15}-\frac5{15}=\frac{13}{15}
\]
\[
b=\frac{13}{15}-\frac{10}{15}=\frac3{15}=\frac15
\]
4)
\[
\frac34+\left(\frac25-y\right)=\frac9{10}
\]
\[
\frac25-y=\frac9{10}-\frac34=\frac{18}{20}-\frac{15}{20}=\frac3{20}
\]
\[
-y=\frac3{20}-\frac8{20}=-\frac5{20}
\]
\[
y=\frac14
\]
5)
\[
a+\frac16=\frac{11}{12}-\frac58
\]
\[
a+\frac16=\frac{22}{24}-\frac{15}{24}=\frac7{24}
\]
\[
a=\frac7{24}-\frac4{24}=\frac3{24}=\frac18
\]
6)
\[
\left(\frac35+p\right)+\frac1{15}=\frac23
\]
\[
p=\frac{10}{15}-\frac9{15}-\frac1{15}=0
\]
7)
\[
\frac{11}{21}-b=\frac3{14}+\frac17
\]
\[
\frac3{14}+\frac17=\frac3{14}+\frac2{14}=\frac5{14}
\]
\[
b=\frac{11}{21}-\frac5{14}
=\frac{22}{42}-\frac{15}{42}
=\frac7{42}=\frac16
\]
8)
\[
\frac45-c=\frac{14}{15}-\frac3{10}
\]
\[
\frac45-c=\frac{28}{30}-\frac9{30}=\frac{19}{30}
\]
\[
c=\frac{24}{30}-\frac{19}{30}=\frac5{30}=\frac16
\]
Проверка выполняется подстановкой: например, в № 6
\[
\left(\frac35+0\right)+\frac1{15}
=\frac9{15}+\frac1{15}
=\frac{10}{15}=\frac23.
\]
Значит, ответы найдены верно.