A good style is to say "Please show me how to solve it . . . "
7x + 3y = 5, (1)
6x - 4y = 3. (2)
Multiply eqn.(1) by 4 (both sides) and the eqn.(2) by 3. You will get
28x + 12y = 20, (1')
18x - 12y = 9. (2')
Now add eqns(1') and (2'). You will get
46x = 29.
Hence, x = .
Having x, now find y from either equation (1) or (2).
Neither the good lady nor Jorel told you what the best
thing to do when you are solving a system of equations
by the addition (or elimination) method and the answer
to the first unknown or variable comes out to be a very
difficult fraction such as x=29/46. In such cases the
best plan is NOT to substitute the bad fraction into one
of the original equations. The best plan is instead to
start over and eliminate the variable x to find y.
They both showed you how to get x = 29/46. But here is
what you should have done to get y:
Begin again and this time eliminate x
Multiply the first equation by -6 and the second equation
through by 7, (Or you could multiply the first equation
by 6 and the second equation through by -7):
Adding the equations term by term gives the equation:
That's easier than substituting 29/46 for x in one
of the original equations and solving for y.
Edwin