Solve each of the following systems of equations by using the method of cross multiplication:
5(x+y)−2(x−y)+1=0,15(x+y)+7(x−y)−10=0.(x≠y,x≠−y).
6x−5y−16=0,7x−13y+10=0.
x+2y+1=0,
2x−3y−12=0.
3x+2y+25=0,
2x+y+10=0.