Question

Solve the following System of equations.
4x+5y=10
8x+5y=30

Answer 1

1. x

=

5

2

−

5

y

4

x=5/2-5y/4

2. x

=

15

4

−

5

y

8

x=15/4-5y/8

Explanation:

Answer 2

`x=5`

`y=-2`

Explanation:

Given the system of equations
`\left \{ {{4x+5y=10} \atop {8x+5y=30}} \right.`, you can use the Elimination Method to solve it.

Multiply the first equation by -1, add both equations and then solve for the variable "x":

`\left \{ {{-4x-5y=-10} \atop {8x+5y=30}} \right.\\........................\\4x=20\\\\x=(20)/(4)\\\\x=5`

And finally, substitute the value of the variable "x" into any original equation and solve for the variable "y". Then:

`4x+5y=10\\\\4(5)+5y=10\\\\20+5y=10\\\\5y=10-20\\\\y=(-10)/(5)\\\\y=-2`