Hi Kristen;
2x+6y=6
7x+8y=5
Let's select one equation and isolate one variable.
I randomly select the first equation and randomly select the variable x.
2x+6y=6
Let's subtract 6y from both sides...
6y+2x+6y=6y+6
2x=6y+6
Let's divide both sides by 2...
(2x)/2=(6y+6)/2
x=3y3
Let's take the second equation and substitute x with 3y3...
7x+8y=5
[(7)(3y3)]+8y=5
(21y+21)+8y=5
21y+21+8y=5
13y+21=5
Let's subtract 21 from both sides...
2113y+21=521
13y=26
Let's divide both sides by 13...
(13y)/13=26/13
A negative number divided by a negative number has a positive result...
y=2
Let's plug this into either equation to establish the value of x...
I randomly select the first equation...
2x+6y=6
2x+[(6)(2)]=6
2x+12=6
Let's subtract 12 from both sides...
122x+12=612
2x=6
Let's divide both sides by 2...
(2x)/2=6/2
x=3
Let's verify our results by plugging both values into the second equation...
7x+8y=5
[(7)(3)]+[(8)(2)]=5
21+16=5
5=5
2/4/2014

Vivian L.