Question 1155473
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I would never solve a system of equations like this using substitution; elimination is far easier.<br>
However, if I did solve it using substitution, I would not solve for y and get an expression involving fractions and then substitute in the other equation.<br>
Remember that, using substitution, you don't need to solve for y or x -- you can solve for 3y, or 7x, or whatever is convenient.<br>
So here is how I would solve this using substitution.<br>
{{{3x+3 = 5y}}} --> {{{6x+6 = 10y}}}<br>
{{{4x+2y=-4}}} --> {{{20x+10y = -20}}}<br>
Now substitute "6x+6" for "10y" in the second equation:<br>
{{{20x+(6x+6) = -20}}}
{{{26x+6 = -20}}}
{{{26x = 26}}}
{{{x = 1}}}<br>
Then finish from there by any method you choose.<br>