equation solve and check

Question

terri lost four pounds over the summer. This is four more than half the weight she wants to lose by December. How much does Terri want to lose?

 

 

 

 

Twelve seventh graders entered the library poster contest. This was three less than fives times the number of 8th graders who entered. How many 8th graders entered the contest

Answer 1

1. Suppose x is the amount she wants to lose by December.  So 4 = x/2 + 4.  Solve this for x:

 

Subtract 4 from both sides:

0 = x/2

 

Multiply both sides by 2:

0 = x.

 

So she wants to lose 0 pounds by December.  Are you sure you copied the question right?

 

2. Suppose x is the number of 8th graders.

 

So 12 = 5x - 3

 

Add 3 to both sides:

15 = 5x

 

Divide both sides by 5

3 = x

 

So there were 3 8th graders.