The rule for secants tells you
EC·ED = EB·EA
(x+4)(x+5) = (x+1)(x+12)
9x+20 = 13x+12 . . . . . . simplify, subtract x²
8 = 4x . . . . . . . . . . . . . . add -12-9x
2 = x
The value of x is 2.
Wdym “these are the right answers”..?
Answer:1) c. 5,9,13,17,21
2) a. a1=8, an=an-1 -2
Step-by-step explanation: 1) an=4n+1
⇒ a1=4×1+1=5
a2=4×2+1=9
a3=4×3+1=13
a4=4×4+1=17
a5=4×5+1=21
2) clearly a1=8 and then the terms of series are decreasing by 2
so, an=an-1 -2
