Solve by using systems by substitution.

Question

2x+3y=0

x+2y=-1

Answer 1

This is two equations two unknowns solved as follows by substitution method:

 

2x+3y=0, 2x=-3y, x= (-3y/2) ... substitute this in the next equation

 

x+2y= -1, (-3y/2)+2y = -1, Muitiply by 2 both sides of the equation

 

2[(-3y/2)+2y] = 2(-1), -3y +4y = -2, y= -2, x=[-3(-2)/2], x =3

 

Therefore x = 3 , and Y = -2

 

Check

 

x+2y=-1, 3+2(-2) = -1, 3-4 = -1, -1 = -1 ... Therefore checks

2(3)+3(-2) = 0, 6-6 =0, 0 =0 ...Therefore checks also