Chapter 7 Exponential and Logarithmic Functions - 7.7 Write and Apply Exponential and Power Functions - 7.7 Exercises - Skill Practice - Page 534: 21

$y=0.241\cdot x^{2.343}$

Let $y=ax^b$. Then our equations are: $6.2=a4^b$ and $23=a7^b$. If we divide the second equation by the first one we get: $1.75^b=(\frac{23}{6.2})\\b=\ln_{1.75}\frac{23}{6.2}\approx2.343$. Then $23=a7^{2.343}\\a=\frac{23}{7^{2.343}}\approx0.241$. Thus $y=0.241\cdot x^{2.343}$