Question 897668
Complementary means they sum to 90.
{{{7x+17+3x-20=90}}}
{{{10x-3=90}}}
{{{10x=93}}}
{{{x=93/10}}}
So then,
{{{7x+17=7(93/10)+170/10}}}
{{{7x+17=651/10+170/10}}}
{{{7x+17=821/10}}}
and
{{{3x-20=3(93/10)-200/10}}}
{{{3x-20=279/10-200/10}}}
{{{3x-20=79/10}}}