Question

Please help. I don't understand​

Answer 1

Length of third side is:
`\mathbf{8m^3-4m^2+3m}`

Explanation:

Perimeter of triangle =
`18m^3+2m^2-m`

Length of side 1=
`5m^3+3m^2-2m`

Length of side 2=
`5m^3+3m^2-2m`

We need to find length of third side.

The formula used is:
`Perimeter \:of\:triangle=Sum\:of\:all\:sides`

Putting values and finding length of third side.

`Perimeter \:of\:triangle=Sum\:of\:all\:sides\\18m^3+2m^2-m=5m^3+3m^2-2m+5m^3+3m^2-2m+Length\:of\:3rd\:side\\18m^3+2m^2-m=5m^3+5m^3+3m^2+3m^2-2m-2m+Length\:of\:3rd\:side\\18m^3+2m^2-m=10m^3+6m^2-4m+Length\:of\:3rd\:side\\Length\:of\:3rd\:side=18m^3+2m^2-m-(10m^3+6m^2-4m)\\Length\:of\:3rd\:side=18m^3+2m^2-m-10m^3-6m^2+4m\\Length\:of\:3rd\:side=18m^3-10m^3+2m^2-6m^2-m+4m\\Length\:of\:3rd\:side=8m^3-4m^2+3m`

So, Length of third side is:
`\mathbf{8m^3-4m^2+3m}`