If $Z+M=88$ and $Z-M=2$,then $M=\ldots \ldots \ldots \ldots . .$

Use the method of elimination to find the solution of the following pair of linear equations: $\frac{x}{4} + \frac{y}{3} = 2, 4x + 3y = 25$.

Solve the following pair of linear equations: $\frac{8}{a} - \frac{9}{b} = 1$ and $\frac{10}{a} + \frac{6}{b} = 7$.

Solve the following pair of equations: $(a \neq 0, b \neq 0)$
$\frac{2}{a} + \frac{3}{b} = 1$
$\frac{1}{a} + \frac{1}{b} = 1$

Form the pair of linear equations for the following problem,and find their solutions (if they exist) by the elimination method:
$A$ lending library has a fixed charge for the first three days and an additional charge for each day thereafter. Saritha paid ₹ $27$ for a book kept for seven days,while Susy paid ₹ $21$ for the book she kept for five days. Find the fixed charge and the charge for each extra day.

Solve the following pair of equations by the method of elimination:
$11x + 13y = 61$
$13x + 11y = 59$