Answer:
x2−8x 7
Step-by-step explanation:
Let x =lenght, y = width, and z =height
<span>The volume of the box is equal to V = xyz </span>
<span>Subject to the surface area </span>
<span>S = 2xy + 2xz + 2yz = 64 </span>
<span>= 2(xy + xz + yz) </span>
<span>= 2[xy + x(64/xy) + y(64/xy)] </span>
<span>S(x,y)= 2(xy + 64/y + 64/x) </span>
<span>Then </span>
<span>Mx(x, y) = y = 64/x^2 </span>
<span>My(x, y) = x = 64/y^2 </span>
<span>y^2 = 64/x </span>
<span>(64/x^2)^2 = 64 </span>
<span>4096/x^4 = 64/x </span>
<span>x^3 = 4096/64 </span>
<span>x^3 = 64 </span>
<span>x = 4 </span>
<span>y = 64/x^2 </span>
<span>y = 4 </span>
<span>z= 64/yx </span>
<span>z= 64/16 </span>
<span>z = 4 </span>
<span>Therefor the dimensions are cube 4.</span>
The intensity of sound which the decibel level of the sound measures 156 is 3.981 × 10³ W/m²
Decibel level, dB = 10log₁₀(I/I₀) where dB = decibel level = 156, I = intensity at 156 dB and I₀ = 10⁻¹² W/m².
Since we require I, making I subject of the formula, we have
dB/10 = log₁₀(I/I₀)
Substituting the values of the variables into the equation, we have
I = 3981.072W/m²
I = 3.981 × 10³ W/m²
So, the intensity of sound which the decibel level of the sound measures 156 is 3.981 × 10³ W/m²
Learn more about intensity of sound here:
brainly.com/question/4431819
