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Mathematics

Solve for x and y, if :

(32)x÷2y+1=1 and 8y164x2=0(\sqrt{32})^x ÷ 2^{y + 1} = 1 \text{ and } 8^y - 16^{4 - \dfrac{x}{2}} = 0

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Answer

Given,

(32)x÷2y+1=1(32)x2y+1=1(25)x2y+1=1[(25)12]x=2y+125×12×x=2y+15x2=y+15x=2y+2x=2y+25 ……(1)\Rightarrow (\sqrt{32})^x ÷ 2^{y + 1} = 1 \\[1em] \Rightarrow \dfrac{(\sqrt{32})^x}{2^{y + 1}} = 1 \\[1em] \Rightarrow \dfrac{(\sqrt{2^5})^x}{2^{y + 1}} = 1 \\[1em] \Rightarrow [(2^5)^{\dfrac{1}{2}}]^x = 2^{y + 1} \\[1em] \Rightarrow 2^{5 \times \dfrac{1}{2} \times x} = 2^{y + 1} \\[1em] \Rightarrow \dfrac{5x}{2} = y + 1 \\[1em] \Rightarrow 5x = 2y + 2 \\[1em] \Rightarrow x = \dfrac{2y + 2}{5} \text{ ……(1)}

Given,

8y164x2=08y=164x2(23)y=(24)4x223y=(2)4(4x2)23y=2162x3y=162x2x=163y ……..(2)\Rightarrow 8^y - 16^{4 - \dfrac{x}{2}} = 0 \\[1em] \Rightarrow 8^y = 16^{4 - \dfrac{x}{2}} \\[1em] \Rightarrow (2^3)^y = (2^4)^{4 - \dfrac{x}{2}} \\[1em] \Rightarrow 2^{3y} = (2)^{4\Big(4 - \dfrac{x}{2}\Big)} \\[1em] \Rightarrow 2^{3y} = 2^{16 - 2x} \\[1em] \Rightarrow 3y = 16 - 2x \\[1em] \Rightarrow 2x = 16 - 3y \text{ ……..(2)}

Substituting value of x from equation (1) in equation (2), we get :

2(2y+25)=163y4y+45=163y4y+4=5(163y)4y+4=8015y4y+15y=80419y=76y=7619=4.\Rightarrow 2\Big(\dfrac{2y + 2}{5}\Big) = 16 - 3y \\[1em] \Rightarrow \dfrac{4y + 4}{5} = 16 - 3y \\[1em] \Rightarrow 4y + 4 = 5(16 - 3y) \\[1em] \Rightarrow 4y + 4 = 80 - 15y \\[1em] \Rightarrow 4y + 15y = 80 - 4 \\[1em] \Rightarrow 19y = 76 \\[1em] \Rightarrow y = \dfrac{76}{19} = 4.

Substituting value of y in equation (1), we get :

x=2y+25=2×4+25=8+25=105=2.\Rightarrow x = \dfrac{2y + 2}{5} = \dfrac{2 \times 4 + 2}{5} \\[1em] = \dfrac{8 + 2}{5} \\[1em] = \dfrac{10}{5} = 2.

Hence, x = 2 and y = 4.

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