I’m stuck on this equation, anyone got the answer?

Answer soon(fast) 15 pts-brainliest? for right answer with small explination a restaurant catered a party for 40 people. a child’s dinner (c) cost $11 and an adult’s dinner (a) cost $20. the total cost of the dinner was $728. how many children and adults were at the party? use the table to guess and check.(i couldn't get the graph onto the question)                                8 children and 32 adults9 children and 31 adults10 children and 30 adults12 children and 28 adults

In the diagram, gef and hef are congruent. what is the value of x

If t8 = 4 and t12 = −2, find the first three terms of the arithmetic sequence.