Question

Susan's math teacher assigned x homework problems on Monday. On Tuesday, she assigned 13 more problems. Over the two days, a total of 21 homework problems were assigned. Which equation could be used to find x, the number of problems assigned on Monday?

A.x - 13 = 21
B.x + 13 = 21
C.21 + x = 13
D.13x = 21

Answer 1

x+(x+13)=21
2x+13=21

as "x" is the number of homework assigned on Monday add that to "x+13", as she assigned the amount she assigned on Monday PLUS 13, and you should get 21