please solve this question

a1=1/2 r=1/4 $7=a1x((1-1/4^7)/1-r); $7=5 of the infinite geometric series. 5 ... 1^2/(1-1/5)^2=25/16 atical induction to prove that the following stat sitive integer n. 7 (n + 1) mial Theorem to expand each binomial and expr form. (x+7)42 X (x+2)42; x^4+28x^3+294x^2+1372x+2401