A solution to a system is when the lines cross, which means that the x and y co-ordinates must be equal. In other words, the equations must be equal.Originally Posted bybeauty13

5x-10y=25

solve for x

Substitute the value of x into this equation

addition requires no paranthesis...

subtract 5 from both sides

solve

When a solution comes out in the form of 0=0 than the two lines that were tested are the same line.

Can you do the other ones now or do you need more help?