Question

solve the following system of linear equations graphically 2x-y-4=0,x+y+1=0

Answer 1

multiply x+y+1=0 with 2
⇒ the 2 equations are 2x-y-4=0 and 2x+2y+2=0
subtract 2 equation from first equation
⇒-3y-6=0
⇒-3y=6
⇒y=6/-3
⇒y=-2
substitute y = -2 in the equation x+y+1=0
⇒x-2+1=0
⇒x=1

Answer 2

2x-y=0
x-y=0

x+y+1=0
x+y=0-1
x-y= –1