Answer:
b = -5
Step-by-step explanation:
[tex]\begin{array}{rcll}(y^{-9})^{b} & = & y^{45}& \\y^{-9b} & = & y^{45} & \text{Multiplied exponents}\\-9b \ln y & =& 45 \ln y & \text{Took the ln of each side}\\-9b & = & 45 & \text{Divided each side by ln y}\\b & = & \mathbf{-5} & \text{Divided each side by -9}\\\end{array}[/tex]
