Question

how to solve these sums?

1) 6y=21-y

2)-4(2-x)=12

3)11m=42+4m

Answer 1

$$\begin{gathered} \left(1\right) \\ 6y=21-y \\ \Rightarrow 6y+y=21 \\ \Rightarrow 7y=21 \\ \Rightarrow y=\frac{21}{7} \\ \Rightarrow y=3 \\ \left(2\right) \\ -4(2-x)=12 \\ \Rightarrow -8+4x=12 \\ \Rightarrow 4x=12+8 \\ \Rightarrow 4x=20 \\ \Rightarrow x=\frac{20}{4} \\ \Rightarrow x=5 \\ \left(3\right) \\ 11m=42+4m \\ \Rightarrow 11m-4m=42 \\ \Rightarrow 7m=42 \\ \Rightarrow m=\frac{42}{7} \\ \Rightarrow m=6 \end{gathered}$$