Question Number 10138 by konen last updated on 26/Jan/17

2^(x+y) =0.125 (0.125)^(x−y) =2 ⇒ x×y=?

Answered by sandy_suhendra last updated on 26/Jan/17

2^(x+y) =(1/8) 2^(x+y) =2^(−3) ⇒x+y=−3 .... (1) ((1/8))^(x−y) =2 2^(−3(x−y)) =2 ⇒ −3x+3y=1 .... (2) (1)×3 ⇒ 3x+3y=−9 (2) ⇒ −3x+3y= 1 −−−−−−− + 6y=−8 ⇒ y=−(4/3) 3x+3(−(4/3))=−9 3x−4=−9 3x=−5 x=((−5)/3) x×y=(((−5)/3))×(−(4/3))=((20)/9)