(a)

The linear equation relating $\"\"$ and $\"\"$ is linear is $\"\"$ .

(b)

Write the linear equation relating $\"\"$ and $\"\"$ .

The linear equation relating $\"\"$ and $\"\"$ is $\"\"$ .

Substitute $\"\"$ in $\"\"$ .

$\"\"$

$\"\"$ .

(a) The linear equation relating $\"\"$ and $\"\"$ is linear is $\"\"$ .

(b) The linear equation relating $\"\"$ and $\"\"$ is $\"\"$ .