Question 176579
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{{{3x - 2y = 23 }}}, EQN 1
{{{x + 5y = -15 }}}, EQN 2
In EQN 2 we get,
{{{5y=-15-x}}}---->{{{cross(5)y/cross(5)=(-15-x)/5}}}
{{{y=(-15/5)-(x/5)}}}
{{{y=-3-(1/5)x}}}, EQN 3, subst in EQN 1:
{{{3x-2(-3-(1/5)x)=23}}}
{{{3x+6+(2/5)x=23}}}
{{{(15x+2x)/5=23-6}}}
{{{17x/5=17}}}---->{{{17x=5*17}}}---->{{{cross(17)x/cross(17)=5*cross(17)/cross(17)}}}
{{{highlight(x=5)}}}, subst in EQN 3:
{{{y=-3-(1/5)(5)=-3-1}}}
{{{highlight(y=-4)}}}
See graph:
{{{drawing(300,300,-5,12,-12,5,grid(1),graph(300,300,-5,12,-12,5,-3-(1/5)x,(3/2)x-(23/2)),blue(circle(5,-4,.20)))}}}-----> RED>>> EQN 2; GREEN>>> EQN 1
thank you,
Jojo</pre>