Use of Substitution to Solve the Systems of Equations

Question

6x-y=22

y=-8

6x+22=-40

6x=-62

x=-31/3

 

Does this look right?

Answer 1

Hi Conny;

6x-y=22

y=-8

(6x)-(-8)=22

Subtracting a negative number is the same as adding a positive number...

6x+8=22

Let's subtract 8 from both sides...

-8+6x+8=22-8

6x=14

Let's divide both numbers by 6..

(6x)/6=14/6

x=14/6

x=7/3

Let's check our work...

6x-y=22

[(6)(7/3)]-(-8)=22

(42/3)+(8)=22

14+8=22

22=22