Find $2^x$ if \begin{align*} 2^x+3^y&=5,\\ 2^{x+2}+3^{y+1} &=18. \end{align*} Thanks!!!!!! :)
2^x + 3^y = 5
2^(x + 2) + 3^(y + 1) = 18 ⇒ 2^2 ( 2^x) + 3 ( 3^y) = 18 ⇒ 4(2^x) + 3(3^y) =18
Let 2^x = m and 3^x = n
So...we have
m + n = 5 ⇒ n = 5 - m (1)
4m + 3n =18 (2)
Sub (1) into (2) and we have that
4m + 3 ( 5 - m) = 18
4m + 15 - 3m = 18
m + 15 = 18
m =18 -15 = 3
So
2^x = 3