How do you solve $4x - 3y = 17$ , $5x + 4y = 60$ ?

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Answer 1 · 2015-11-13T18:33:29

$x=8$ , $y=5$ .

From the first equation, you know that

$x=(17+3y)/4$

Substitute this value in the second equation:

$5((17+3y)/4)+4y=60 -> (85+15y)/4+4y=60$

We can multiply everything by $4$ to get rid of the denominator:

$85+15y+16y = 240$

Isolating the $y$ terms:

$31y = 155 -> y=155/31 = 5$

Now that we knoe that $y=5$ , we can obtain $x$ by substitution:

$4x-3y=17 -> 4x-15=17 -> 4x=32$

and thus $x=8$

How do you solve 4x - 3y = 174x - 3y = 17, 5x + 4y = 605x + 4y = 60?