D1.21 For systems with input r(t) and output y(t) that are described by the following equations, find the system transfer functions: (a) 。,ル d²y dy +7y = 6r di dt2 Ans. 6/ (s? + 3s + 7) (b) d³y 2 +4y...

plz provide answer for part d only

Extracted text: D1.21 For systems with input r(t) and output y(t) that are described by the following equations, find the system transfer functions: (a) 。,ル d²y dy +7y = 6r di dt2 Ans. 6/ (s? + 3s + 7) (b) d³y 2 +4y = -5 dy d²r dr +8 dr? dr? dt Ans. (-5s² + 8s) / (s³ + 6s² + 2s +4) y(t) = 8r(t – 3) Ans. 8e-3 (d) dxi = -3x1 + x2 +4r dt dx2 = -2x1 -r dt y= X1 - 2x2 Ans. (6s +21)/(s² + 3s + 2)