find the first four terms of the sequence an=n(n-7)

Question

A) -6, -8, -12, -16

B) 6, 8, 12, 16

C) -6, -10, -12, -12

Answer 1

"N" is the number of the term (1st term is 1, 2nd term is 2, etc.), here's how the equation would be solved. 

 

x = n * (n-7) 

 

For the first term, x = 1 * (1-7) or or x = 1 * -6 or x =-6. From there, we can eliminate B as a possible answer choice because the first term is -6 and not 6. 

 

For the second term, x = 2 * (2-7) or x = 2 * -5 or x = -10. From there, we know that the second term is -10. C's looking pretty good at this point. 

 

For the third term, x = 3 * (3-7) or x = 3 * -4 or x = -12. Again C is looking good. 

 

Finally, for the fourth term, x = 4 * (4-7) or x = 4 * -3 or x = -12. C's the correct answer.