Use the distributive property and combine the like terms.
8n + 3 (5+4n)

20n+15

Step-by-step explanation:

First, you need to use the distributive property to multiply 3 to the numbers inside the parenthesis.

After distributing:

8n+15+12n

Then, you combine like terms which are 8n and 12n.

To combine like terms, you either add or subtract but in this case, you add.

Now you get

20n+15

< xcy ≅ < xby

step-by-step explanation:

in δcax and δbax,

so, δcax ≅ δbax (side-angle-side or sas)

since δcax ≅ δbax, we can conclude < acx ≅ < abx

in δacy and δaby,

so, δacy ≅ δaby (side-angle-side or sas)

since δacy ≅ δaby, we can conclude < acy ≅ < aby

now,

< acy ≅ < aby

=> < acx + < xcy ≅ < abx + < xby

=> < acx + < xcy ≅ < acx + < xby   (since < acx ≅ < abx already proved above)

subtracting < acx from both sides, we get

< acx + < xcy -< acx ≅ < acx + < xby -< acx

cancelling out < acx and -< acx from both sides, we get

< xcy ≅ < xby (proved)