Add the following weights:
13 lb 7 oz
+ 10 lb 2 oz
lb
OZ

23 pounds and 9 ounces (23lb 9 oz)

Step-by-step explanation:

You can add the pounds together and the ounces together separetly.  As long as the ounces are less than 16 (since 16 ounces=1 pound), you wont hvae to convert those ounces into pounds.  So you can simply add the numbers up to get 23 pounds and 9 ounces

< 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)