Question 657727
Okay for elimination we need to eliminate something.  I'll choose to eliminate x.  I need both x's to be equal.  So I'll multiply the first equation by 5 and the second equation by 3.

3x-5y=30 ... (i)
15x - 25y = 150 ... (iii)

5x + 7y = 4 ... (ii)
15x + 21y = 12 ... (iv)

Now eliminate.  I will subtract equation 4 from equation 3.

15x - 25y = 150
-)15x+21y = 12
________________
0x -46y = 138
y = -138/46
y = 3

now I will sub y = 3 into equation 1.

3x - 5(3) = 30
3x - 15 = 30
3x = 45
x = 45/3
x = 15

Therefore, x = 15, y = 3.  This was solved via elimination method.