U-substitution with a Definite Integral (4-R p310 #67)

 U-substitution with a Definite Integral (4-R p310 #67)

When you use u-substitution with a definite integral, you don't have to switch back to make an expression in terms of x.  Since any definite integral is the signed area, it is just a number.  After finding the anti-derivative in terms of you, the FTC can be used to arrive at the answer.