Question 1097851
<br>I will assume the second equation is supposed to show -0.3y instead of -0.3x....<br>
Are you sure you are supposed to use substitution for this?  It is very well suited for solving by elimination; multiplying the second equation by 2 makes it easy.<br>
{{{3.4x + 1.3y = 15.2}}}
{{{3.4x - 0.6y = 22.8}}}
{{{1.9y = -7.6}}}
{{{y = -4}}}
{{{1.7x - 0.3(-4) = 11.4}}}
{{{1.7x - 1.2 = 11.4}}}
{{{1.7x <= 12.6}}}
{{{x = 8}}}<br>
If I were told that I had to solve this using substitution, then, since 3.4 is twice 1.7, I would solve the second equation for 1.7x (there is nothing in the substitution process that says you have to solve for "x" or "y" by itself):<br>
{{{1.7x-0.3y = 11.4}}}
{{{1.7x = 0.3y+11.4}}}<br>
Then<br>
{{{3.4x+1.3y=15.2}}}
{{{2(0.3y+11.4)+1.3y = 15.2}}}
{{{0.6y+22.8+1.3y = 15.2}}}
{{{1.9y = -7.6}}}
{{{y = -4}}}
{{{1.7x-0.3(4) = 11.4}}}
{{{1.7x-1.2 = 11.4}}}
{{{1.7x = 12.6}}}
{{{x = 8}}}