Question

Solve this simultaneous linear equation=X+y=4and2x-y=5​

Answer 1

• x+y=4---(1)
• 2x-y=5---(2)

From eq(1)

`\\ \sf\longmapsto x+y=4`

`\\ \sf\longmapsto x=4-y\dots(3)`

• Put values in eq(2)

`\\ \sf\longmapsto 2x-y=5`

`\\ \sf\longmapsto 2(4-y)-y=5`

`\\ \sf\longmapsto 8-2y-y=5`

`\\ \sf\longmapsto 8-3y=5`

`\\ \sf\longmapsto 8-5=3y`

`\\ \sf\longmapsto 3y=3`

`\\ \sf\longmapsto y=(3)/(3)`

`\\ \sf\longmapsto y=1`

Put value in eq(3)

`\\ \sf\longmapsto x=4-y`

`\\ \sf\longmapsto x=4-1`

`\\ \sf\longmapsto x=3`