Can someone solve numbers 3 and 4, and show your work plz

3 would turn into

b= b^(6+8)

b= ^(3+4)

b^14/b^7 or 1/2

4 would be

a^(14+10)  /  a(5+7)  

a^24  / a^12    or 1/2

= 5

step-by-step explanation:

to find the 15th term substitute n = 15 into the nth term formula

= (- 3 × 15 ) + 50 = - 45 + 50 = 5