D dnntau May 2010 37 0 May 30, 2010 #1 If 8^x = 15 and 8^y = 25, then 8^(2x+y) = A) 55 B) 80 C) 250 D) 5,625 When I just input it into the calculator I get 4.676805239 and when I do 15 x 2 + 25 I get 55 but the answer is 5,625.

If 8^x = 15 and 8^y = 25, then 8^(2x+y) = A) 55 B) 80 C) 250 D) 5,625 When I just input it into the calculator I get 4.676805239 and when I do 15 x 2 + 25 I get 55 but the answer is 5,625.

S sa-ri-ga-ma Jun 2009 806 275 May 30, 2010 #2 dnntau said: If 8^x = 15 and 8^y = 25, then 8^(2x+y) = A) 55 B) 80 C) 250 D) 5,625 When I just input it into the calculator I get 4.676805239 and when I do 15 x 2 + 25 I get 55 but the answer is 5,625. Click to expand... \(\displaystyle 8^{2x} = 15^2 and ; 8^y = 25\) So \(\displaystyle 8^{(2x+y)} = (15^2)(25) = ....?\)

dnntau said: If 8^x = 15 and 8^y = 25, then 8^(2x+y) = A) 55 B) 80 C) 250 D) 5,625 When I just input it into the calculator I get 4.676805239 and when I do 15 x 2 + 25 I get 55 but the answer is 5,625. Click to expand... \(\displaystyle 8^{2x} = 15^2 and ; 8^y = 25\) So \(\displaystyle 8^{(2x+y)} = (15^2)(25) = ....?\)

D dnntau May 2010 37 0 May 30, 2010 #3 Thank you so much. Me and my sister together couldn't figure that one out. (Rofl)