a: =>7(135:x-13)=14
=>135:x-13=2
=>135:x=15
=>x=9
b: =>11x-66-4x=11
=>7x=77
=>x=11
\(120+\left(135:x-13\right)\cdot7=134\)
\(\Rightarrow\left(135:x-13\right)\cdot7=134-120\)
\(\Rightarrow\left(135:x-13\right)\cdot7=14\)
\(\Rightarrow135:x-13=14:7\)
\(\Rightarrow135:x=2+13\)
\(\Rightarrow135:x=15\)
\(\Rightarrow x=135:15\)
\(\Rightarrow x=9\)
_______________
\(11\cdot\left(x-6\right)=4\cdot x+11\)
\(\Rightarrow11\cdot x-66=4\cdot x+11\)
\(\Rightarrow11\cdot x-4\cdot x=11+66\)
\(\Rightarrow7\cdot x=77\)
\(\Rightarrow x=77:7\)
\(\Rightarrow x=11\)
\(a,120+\left(135\div x-13\right)\times7=134\)
\(\Rightarrow\left(135\div x-13\right)\times7=14\)
\(\Rightarrow135\div x-13=2\)
\(\Rightarrow135\div x=15\)
\(\Rightarrow x=135\div15=9\)
\(b,11\times\left(x-6\right)=4\times x+11\)
\(\Rightarrow11\times x-66=4\times x+11\)
\(\Rightarrow11\times x-4\times x=66+11\)
\(\Rightarrow\left(11-4\right)\times x=77\)
\(\Rightarrow7\times x=77\Leftrightarrow x=11\)
\(120+\left(\dfrac{135}{x}-13\right).7=134\\ \Rightarrow\left(\dfrac{135}{x}-13\right).7=134-120\\ \Rightarrow\left(\dfrac{135}{x}-13\right).7=14\\ \Rightarrow\dfrac{135}{x}-13=\dfrac{14}{7}=2\\ \Rightarrow\dfrac{135}{x}=2+13=15\\ \Rightarrow x=135:15=9\)
\(11\left(x-6\right)=4x+11\\ \Rightarrow11x-66-4x-11=0\\ \Rightarrow7x=77\\ \Rightarrow x=\dfrac{77}{7}\\ \Rightarrow x=11\)