SOLUTION: 3x+7y=21 3x-3x+7y=3x+21 7y/7=3x+21 ----- 7 3x/7+21/7 3x/7+3

Algebra ->  Linear-equations -> SOLUTION: 3x+7y=21 3x-3x+7y=3x+21 7y/7=3x+21 ----- 7 3x/7+21/7 3x/7+3      Log On


   



Question 185395: 3x+7y=21
3x-3x+7y=3x+21
7y/7=3x+21
-----
7
3x/7+21/7
3x/7+3

Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
3x+7y=21
.
Subtracting 3x from both sides:
3x+7y-3x = -3x+21
7y = -3x+21
.
Now, dividing both sides by 7:
y = (-3/7)x + 3 (this is what they're looking for)
.
This is now in "slope-intercept" form:
y = mx + b
where
m is slope
b is the y-intercept at (0,b)
.
So, from:
y = (-3/7)x + 3
m is -3/7
b the y-intercept is at (0, 3)