2) 5( a + b )^2/ ( a + b)^2 = 5/1 = 5
4) (q + 7)^2/ ((7-q)(7+q))^2 = q + 7\ (7 - q)^2
6) (c-4)(c+4)/(c-4)^2 = c + 4\ c - 4
8) c^2(a-b)(a+b)/x(a-b)^2 = c^2( a + b)\ x( a - b)
a2=a1+d=17,
a6=a1+5d=65;
d=17-a1,
a1+5(17-a1)=65,
-4a1=-20,
a1=5,
S6=(a1+a6)6/2=(5+65)*3=210