Question

Solve for x and y.

4x-3y=16
-2x+4y=-2

DUE 2/7/17!

Answer 1

`\left \{ {{4x-3y=16\:(I)} \atop {-2x+4y=-2\:(II)}} \right.`

Multiply the 2nd equation by (-4). This will eliminate the x's when you add the two new equations together.

`\left \{ {{4x-3y=16\:\:\:\:\:\:\:\:\:\:} \atop {-2x+4y=-2\:*(-4)}} \right.`

`\left \{ {{\diagup\!\!\!\!4x-3y=16} \atop {-\diagup\!\!\!\!4x+8y=-4}} \right.`
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`5y = 12`

`\boxed{\boxed{y = (12)/(5)}}\end{array}}\qquad\quad\checkmark`

Let's replace the value found in the first equation:

`4x-3y=16\:(I)`

`4x-3*( (12)/(5)) =16`

`4x - (36)/(5) = 16`
least common multiple (5)

`(20x)/(\diagup\!\!\!\!5) - (36)/(\diagup\!\!\!\!5) = (80)/(\diagup\!\!\!\!5)`

`20x - 36 = 80`

`20x = 80 + 36`

`20x = 116`

`x = (116)/(20) (/4)/(/4) \to\: \boxed{\boxed{x = (29)/(5) }}\end{array}}\qquad\quad\checkmark`