SOLUTION
This question simply means we should find the value of x,
[tex]2\mleft(x+5.3\mright)=4.2[/tex]First we expand by using 2 to multiply the items in the bracket, we have
[tex]\begin{gathered} 2\times x+2\times5.3=4.2 \\ 2x+10.6=4.2 \\ 2x=4.2-10.6 \\ 2x=-6.4 \\ \text{dividing both sides by 2, we have } \\ \frac{2x}{2}=\frac{-6.4}{2} \\ x=-3.2 \end{gathered}[/tex]Hence the answer is -3.2
