I'll treat these like they're two seperate problems because how you set it up they're not together. If it's one whole problem please tell me and I'll solve it that way. :-)
First one: 3x+9+8x + 12
Collect like terms and simplify
(3x+8x)+(9+12)
11x+21
Second one: 2x + 6+x² + 6x + 9
Collect like terms and simplify
8x+15+
Hope this helps you, have a BLESSED and wonderful day, as well as a safe one!
-Cutiepatutie ☺❀❤
After using the slope formula your answer would be 5/0.1 but when simplifying your answer is 50
33.3 square feet
Explanation: 8+8= 16+4= 20 + the top which should not be much more than 8.
Hope this helps:)