Tutorial Exercise Find dy/du, du/dx, and dy/dx. y = U-1, u= x3 + 9x 2 Step 1 First, differentiate y = u" with respect to u. dy -2 du -u-2 Step 2 Now, differentiate u = x3 + 9x2 with respect to x. du dx 3x + 18x 3.12 + 18x Step 3 Now use the Chain Rule to find dy dx dy _ dy . du dx du dx = (-1-2 )(3x2 + 18x) Substitute U = x3 + 9x2. dx dy = - (x3 + 9x2) -2 - (3x2 + 18x) 6 23 + 9x2 + 18x + 108 x x+93 X Submit Skip (you cannot come back)