Question

Please solve it fast friends. Its quite urgent

Answer 1

(a+c)(h+c-20)÷2(b-a)
(a+c)(h+c-20)÷2b+a
a+a+c+c+h-20÷2b
2a+2c+h-10b
2(a+c)+h-10b

Answer 2

Given that A1=a A2=b.An=2 A2=b&An=c. a+d=b. d=b-a. a+(n-1)d=c. then value of n=b+c-2a/b-a. we know that sum of A.P=n/2(2a+(n-1)d). putting these valves,=b+c-2a/2(b-a)(2a+c-a)then=(b+c-2a)(a-c)/2(b-a).Hence proved