Answer:
35.03
Explanation:
The estimated regression line is
y^=36+0.81 X1-1.7 X2.
The predicted value of life expectancy of a rat that was given 3 units of protein daily, and who had 2 agents of X2 added to the rats can be found by putting X1=3 and X2=2 in the above estimated regression equation.
y^=36+0.81(3) - 1.7(2)
y^=36+2.43-3.4
y^=38.43-3.4
y^=35.03.