Answer:
The value of Y is - 9.
Explanation:
1. Let's start with the first equation to find out the value of Y.
7x + 2y = 3
2y = 3 - 7x
y = 3/2 - 3 1/2x
2. Now let's work with the second equation to find out the value of Y.
x - 3y = 30
x - 3 (3/2 - 3 1/2x) = 30
x - 9/2 + 21/2 x = 30
x + 21/2 x = 30 + 9/2
2x + 21x = 60 + 9
23x = 69
x = 69/23
x = 3
3. Now let's substitute the value of X in the first equation, to find out the value of Y.
7 (3) + 2y = 3
21 + 2y = 3
2y = 3 - 21
2y = -18
y = - 9
4. Proof of the values of X and Y on the second equation
x - 3y = 30 (x = 3 and y = -9)
3 - 3 (-9) = 30
3 + 27 = 30
30 = 30 This means that the values of x and y are correct.