How do you solve 21x-15y=24 and 6x+10y=24?

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Answer 1 · 2018-04-03T12:28:33

$x=2$
$y=6/5$

$21x-15y=24$ ---(1)
$6x+10y=24$ --- (2)

From (2),

$6x=24-10y$
$x=4-5/3y$ --- (3)

Sub (3) into (1).

$21(4-5/3y)-15y=24$
$84-35y-15y=24$
$60=50y$
$y=6/5$ --- (4)

Sub (4) into (3)
$x=4-5/3times6/5$
$x=2$

Answer 2 · 2018-04-03T12:39:24

$x=2$ and $y=6/5$

As both equation equal 24, equate them:

$21x-15y=6x+10y$

$15x-15y=10y$

$15x=25y$

$3x=5y$

Substitute this into $6x+10y=24$

$6x=2$ $xx$ $3y$

$=>$ $(2$ $xx$ 5y)+10y=24

$=>$ $10y+10y=24$
$=>$ $20y=24$
$=>$ $y=6/5$
Substitute $y=6/5$ into either equation to find $x$

$6x+10$ $xx$ $6/5=24$
$6x+12=24$
$x=2$