To solve this exercise you have to solve each system of equations.
a)

To solve this equation system you have to equal both equations and solve for x:

- Pass -6x to the left side of the equation by applying the opposite operation to both sides of it

- Add 5 to both sides of the equal sign:

- Divide both sides by 10

- Replace the value of x in one of the equations and solve for y:

The solution for this equation system is (3,7)
b)

Replace the second equation into the first one:

- Distribute the multiplication on the parentheses term:

-Subtract 10x to both sides of the expression:

-Subtract 84 to both sides of the equal sign:

-Divide both sides by -24

- Replace the value of x in the second equation and solve for y:

The solution for this equation system is (4,14)
c)

- Write the second equation for y:

- Replace the expression in the first equation

-Distribute the multiplication on the parentheses term

- Subtract 69 to both sides of the equal sign

-Divide both sides by -45

-Replace the value of x in the expression obtained for y and solve:

The solution of this equation system is (2,-1)
d)

- Write the second equation for y:

-Replace the expression in the first equation:

-Distribute the multiplication on the parentheses term:

-Subtract 52 to both sides of the equation:

-Divide both sides by -29

-Replace this value in the expression obtained for y:

The solution to this equation system is (76/29,450/29)
The answer for this exercise is:
a → (3,7)
c → (2,-1)
b → (4,14)
e → (4,20)