Question

When using the method of combining equations in solving a system of equations, do you combine the y's too? Like turn them into 2y?

Answer 1

if y=a
and y=b

then a = b

Answer 2

i spose:

2y = a+b ; but y=a

a+a = a+b

a = b
---------------------

2y = a+b ; but y=b

b+b = a+b

b = a

Answer 3

you are trying to accomplish eliminating one of the variables x or y,
add( or subtract) the equations ,
and then solve for the variable that is left, and then plug in what you found and solve for the other variable.

here is an example:

-2x + 3y = 8
3x - y = -5

multiply all terms in the second equation by 3
-2x + 3y = 8
9x - 3y = -15
add the two equations
7x = -7
x= -1
•substitute x by -1 in the first equation
-2(-1) + 3y = 8

solve the above equation for y
2 + 3y = 8
3y = 6
y = 2

write the solution to the system as an ordered pair

(-1,2)

check the solution obtained

Answer 4

Thanks guys. :)