8. write an equation of the form an = a1 + d(n - 1) that would
describes the nth term of the arithmetic sequence 7, 10, 13,

a(n) = 7 + 3(n - 1)

Step-by-step explanation:

Notice that every term of the sequence 7, 10, 13, 16 is 3 more than the previous term.  That tells us this is an arithmetic sequence with first term 7 and common difference (d) 3.

Adapting the given equation, we end  up with

a(n) = 7 + 3(n - 1)

c.

step-by-step explanation:

she should of added 9^2 and 12^2. that is because it is a^2+b^2=c^2. c^2 is the hypotenuse and should always be bigger than the other two numbers. which is why she should of added 9 squared and 12 squared together instead of 15 squared.