Question

If x+y=8 and 2^x+2^y=40,then find x,y

Answer 1

Answer:

y= 5 & y = 3  

x= 3 & 5

Step-by-step explanation:

x+y= 8 ------(I) & 2^x+ 2^y = 40--------(II)

x+y = 2^3 or x= 2^3 -  y

from (II)  

2^(2^3-y) + 2^y =40

2^2^3/2^y  + 2^y = 40

2^8/2^y + 2^y = 40

 or 256 +( 2^y}^2 = 40* 2^y

let 2^y = a

so 256 + a^2 = 40 a

a^2 - 40 a + 256 =0

a=[40 +_sqrt{40^2 - 4*256)]/2

 =[40 +_ 24]/2

= 20+_ 12

so a= 32 & a= 8

so 2^y = 32 & 2^y = 8

so 2^y = 2^5 & 2^y = 2^3

so y= 5 & y = 3  

so x= 3 & 5

Answer 2

Answer:

have a nice day ........