Solve the System of Equations...?

Question

Can anyone help me solve this system of equations and teach me how they solved it. 

3(r-3q)= -4(1+p) 
2(p-3q+4r)= -9 
3(2p+q)+5r= -1

Answer 1

Step 1:

The system of equations are , and

.

Rewrite the equations are , and .

Solve the system of equations by elimination method.

Eliminate one variable by using two pairs of equations.

Add the and equations to eliminate the one variable.

Solve the system of two equations containing and to find value.

Divide each side by .

Step 2:

Substitute into system of equation of and find value.

Subtract from each side

Substitute values of and into one of the original equation to find value.

Add to each side

The solution is and .

Solution :

The solution of the system is .