Question

How do solve the following linear system?: `2x +5y - 21 = 0 , 3x – 2y = 7`?

Answer 1

`2x+5y-21=0-------(1)`
`3x-2y-7=0-------(2)`
By cross multiplication we have
`x/(5*(-7)-(-2)*(-21))=y/(-21*3-(-7)*2)`

`=1/(2*(-2)-5*3)`

`=>x=77/19`

`=>y=49/19`