Question

HELP please? If a⊗b=2a-b, determine the value of x such that 2⊗10.

Answer 1

I'm going to assume this is the same as your previous question:
If a ⊗ b=2a-b, determine the value of x such that 2 ⊗ x=10. (the x=10 is missing in the question)

You can view the \(\otimes\) operation as doing:
\(\color{red}{a} \otimes \color{blue}{b} = 2\color{red}{a} - \color{blue}{b}\)
In words, think that the first element gets multiplied by 2, and then you subtract off the second element

So what is \(2 \otimes x\) ?

\(\begin{align}\color{red}{2}\otimes\color{blue}{x}&=2\color{red}{(2)}-\color{blue}{x}\\&=4-x \end{align}\)

So now,

\(~~~~~~~~~~~2 \otimes x = 10 \\ \implies 4-x = 10\)

Can you solve for x now?