Question

Arthur writes the equation a = 10 b - 7. He wants to rewrite it in terms of b. In Arthur's first step, what value should he add to both sides of the equation?
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Answer 1

To rewrite the equation \( a = 10b - 7 \) in terms of \( b \), Arthur should first aim to isolate the term that involves \( b \).

The first step is to eliminate the \(-7\) on the right side of the equation. To do this, he should add \( 7 \) to both sides of the equation.

So, he should add \( 7 \) to both sides:

\[
a + 7 = 10b - 7 + 7
\]

This simplifies to:

\[
a + 7 = 10b
\]

Thus, the value Arthur should add to both sides of the equation is \( 7 \).