Question

Use substitution to determine the solutions of the system of equations. Write your solution as an ordered pair .y = - 2x - 7 and 2y - x = 1

Answer 1

i) y=-2x-7 and (ii) 2y-x=1

substitute i into ii

and solve for X

2(-2x-7)-x=1

-4x-14-x=1

-5x-14=1.........adding similar terms

-5x=15

X=-3......by dividing both side by -5

Then to solve for Y substitute X=-3 into one equation.

take eqn i) Y=-2(-3)-7

Y=6-7

Y=-1

in order pair form (X,Y)=(-3,-1)