7y-3(9y+7)/5 = -5
y = -1/2
so, x = 1/2
5x - 9y = 7,
7y - 3x = -5
solve using any algebraic method
3 answers
Steve can you explain how you got the answer to this??
sure. the first equation
5x - 9y = 7
tells us that x = (9y+7)/5
Just plug that into the 2nd equation, and you get
7y-3(9y+7)/5 = -5
fractions are a nuisance, so multiply through by 5:
35y - 3(9y+7) = -25
35y - 27y - 21 = -25
8y = -4
y = -1/2
Now plug that value into either equation and solve for x.
5x - 9y = 7
tells us that x = (9y+7)/5
Just plug that into the 2nd equation, and you get
7y-3(9y+7)/5 = -5
fractions are a nuisance, so multiply through by 5:
35y - 3(9y+7) = -25
35y - 27y - 21 = -25
8y = -4
y = -1/2
Now plug that value into either equation and solve for x.
3 answers