Question

$2^{x-2} = 128$

Answer 1

Step-by-step explanation:

गुणनफल का आवश्यक योगफल : 2 x 128 + 4 x 32 + 8 x 8 + 16 x 2 + 32 x 1/2

= 256 + 128 + 64 + 32 + 16, जो प्रथम पद 256 और सार्व अनुपात 1/2 के साथ समान्तर श्रेणी है |

अब S_n = a(1-r^n) / 1 - r

=> S_5 = 256 [ 1 - (1/2)^5 ] / 1 - (1/2)

=> = 256 [ 1 - (1/32) ] /(1/2)

=> = 512 [ 32 - 1 / 32 ]

=> = 16 x 31

=> = 496

Answer 2

Answer:

$2 {}^{ x- 2} \\ = 128$

$2 {}^{x - 2} = 2 {}^{7}$

x-2=7

therefore... x = 9