Question 190154
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Given Line Eqns. 
{{{15x-10y=-1 }}}, {{{ (red(EQN1))}}}
{{{5y=1+10x}}}, {{{(red(EQN2))}}}



In EQN 2, isolate "y" then subst. value to {{{red(EQN1)}}}
{{{cross(5)y/cross(5)=(1+10x)/5}}}
{{{y=(1/5)+(10/5)x}}}
{{{y=(1/5)+2x}}}, {{{red(EQN3)}}} 


Then,
{{{15x-10(highlight(1/5+2x))=-1}}}
{{{15x-10/5-20x=-1}}}
{{{15x-20x=-1+10/5=-1+2}}}
{{{-5x=1}}} ---> {{{cross(-5)x/cross(-5)=1/-5}}}
{{{red(x=-1/5)}}}, subst. in {{{red(EQN3)}}}


{{{y=(1/5)+2(highlight(-1/5))}}}
{{{y=(1/5)-2/5}}}
{{{red(y=-1/5)}}}


These 2 lines intersect at point (-1/5,-1.5) or (-0.20,-0.20)


We'll see,
{{{drawing(400,400,-2,2,-2,2,graph(400,400,-2,2,-2,2,(15x+1)/10,(1+10x)/5),circle(-1/5,-1/5,.04))}}} ---> {{{red(RED=EQN1)}}}; {{{green(GREEN=EQN2)}}}


Thank you,
Jojo</font>