The two equations given are
6x - 3y = 15
Dividing both sides of the equation by 3, we get
2x - y = 5
y = 2x - 5
And
7x + 4y = 10
Now we put the value of y determined from the first equation in the second equation, we get
7x + 4y = 10
7x + 4(2x - 5) = 10
7x + 8x - 20 = 10
15x - 20 = 10
15x = 10 + 20
15x = 30
x = 30/15
= 2
Putting the value of x in the second equation we get
7x + 4y = 10
(7 * 2) + 4y = 10
14 + 4y = 10
4y = 10 - 14
4y = -4
y = -(4/4)
= - 1
So the value of x is 2 and the value of y is -1.