How do you solve the system $3y-8x=24 and 3y+2x=9$ ?

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Answer 1 · 2016-07-27T11:44:15

$x=3/2$

I have taken you just to this point so that you can complete the whole thing.

The trick is to eliminate one of the variables so that you only have one unknown left.

Write as

$" "3y-8x=24$
$" "ul(3y+2x=color(white)(2)9) " "larr" Subtract"$
$" "0-10x=15$

Multiply both sides by $(-1)$

$+10x=-15$

Divide both sides by 10

$x=-(cancel(15)^3)/(cancel(10)^2)" "larr" Divide top and bottom by 5"$

$x=3/2$

.~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Now just substitute $3/2$ for $x$ in any of the given equations and solve for $y$

$color(green)("I have left that for you to do!")$

How do you solve the system 3y-8x=24 and 3y+2x=93y-8x=24 and 3y+2x=9?