Question

How do you solve the following system?: #9x +12y = 7 , -2x - 21y = -41#

Answer 1

`x=-2.1andy=2.15`

Explanation:

Let,`9x+12y=7..............(1)`
`-2x-21y=-41.................(2)`
`[(1)equationxx(-2)]:-18x-24y=-14...................(3)`
`[(2)equationxx(9)]:-18x-189y=-369.....................(4)`

`Now[(3)-(4)]:` `cancel(-18x)-24y+cancel(18x)+189y=-14+369`

or,`165y=355`

so,`y=2.15`

Now substitute this value in (1)no. equation:

`9x+12(2.15)=7`

or,`x=-2.1`