Question

How do you solve the following system: `5x + 8y = -2, 3x - 4y = -10`?

Answer 1

`x = -2 and y = 1`

Explanation:

For the elimination method. the coefficients of one of the variable should be the same. It is fantastically easier if they can become additive inverses - same number, different signs. +5 and - 5 add to 0.

`" "5x + 8y = -2 ..................." equ A"`
`" " 3x - 4y = -10....................."equ B"`
`B xx 2: " "6x - 8y = -20 .................... "equ C"`

`A + B:" " 11x " "= -22`
`" " x = -2`

Substitute in A: `5(-2) + 8y= -2` =
`" "-10+8y = -2`
`" " 8y = -2 + 10`
`" " 8y = 8`
`" " y = 1`