The solution set of a pair of equations $x+y-2=0$ and $2x+2y-4=0$ is $\ldots \ldots \ldots . . . .$

Solve the following pair of linear equations:
$\frac{x}{a} + \frac{y}{b} = a + b$
$\frac{x}{a^{2}} + \frac{y}{b^{2}} = 2, \quad a, b \neq 0$

The two-digit number whose digit at the unit's place is $x$ and the digit at the ten's place is $y$ is three times the sum of its digits. This statement is written as $\ldots \ldots \ldots \ldots .$

Solve the following pairs of equations by the cross-multiplication method:
$4x + 6y = 11$
$5x - 8y = 6$

The standard form of the equation $5y = -2x + 3$ is........

$x$ years ago,the sum of the ages of a mother,father,and two children was $y$ years. What will be the sum of their ages after $z$ years?