# How do you solve using elimination of #x-15y=3# and #3x+y=21#?

##### 2 Answers

#### Explanation:

Given

[1]

[2]

**Eliminate** the

#{: ([2],color(white)("XXX"),,"(",3x,+y,"=",21,")"), (3xx[1],color(white)("XXX"),-,"(",3x,-45y,"=",9,")") :}#

[4]

[5]

**Eliminate** the

#{: ([1],color(white)("XXX"),,"(",x,-15y,"=",3,")"), (15xx[2],color(white)("XXX"),+,"(",45x,+15y,"=",315,")") :}#

[6]

[7]

I found:

#### Explanation:

We can multiply the first equation by

So:

use this into the first equation: