Can someone check my math homework? I have to set up an equation... my math teacher said that I didn't show how I set up the equation. can someone show me how to do that please? My work is under the question.

7. Anne is seven years younger than her brother, Brandon. Anne is 23. Let B represent Brandon’s age.

B=23+7=30
B=30
Brandon is 30 years old.

8. Last Friday, the Cougars lost to the Tigers in basketball by 15 points. The Tigers scored 72 points. Let C represent the Cougars' score.

C=72-15=57
C = 57
Cougar’s score is 57.

9. Mary scored 36 points, which is half as many points as Lashawna scored. Let L represent the points Lashawna scored.

L=36*2=72
L=72
Lashawna’s score is 72.

10. Joey owns a small bakery and today Phoebe has ordered c cookies. If Joey boxes the cookies by the dozen and has packed 20 boxes, how many cookies has Phoebe ordered? Let c represent the number of cookies.

C=12*20=240
C=240
Phoebe ordered 240 cookies.

Right.