$$\dfrac{C(s)}{R(s)} = \dfrac{X_1}{1-X_1Y_1}$$

$$\dfrac{C(s)}{R(s)} = \dfrac{X_2}{1-X_1Y_1}$$

$$\dfrac{C(s)}{R(s)} = \dfrac{X_1X_2}{1-X_1Y_1}$$

$$\dfrac{C(s)}{R(s)} = \dfrac{X_1+X_2}{1-X_1Y_1}$$

$$-\dfrac{1}{41}$$

$$-\dfrac{3}{41}$$

$$-\dfrac{5}{41}$$

$$-\dfrac{6}{41}$$

$$-\dfrac{8}{9}$$

$$\dfrac{4}{5}$$

$$180$$

$$10$$

a+2

a+3

a+5

a+6

$$\dfrac{ab}{1+b-abc}$$

$$\dfrac{ab}{1-b-abc}$$

$$\dfrac{ab}{1-b+abc}$$

$$\dfrac{ab}{1-ab+abc}$$

$$\dfrac{abcdg}{1-abcde}$$

$$\dfrac{abcde}{1-cg-bcdf}$$

$$\dfrac{abcde}{1-cg-cgf}$$

$$\dfrac{abcde}{1+cg+cgf}$$

$$\dfrac{C}{R}=\dfrac{G_1+G_2}{1-G_1H_1}$$

$$\dfrac{C}{R}=\dfrac{G_1+G_2}{1-G_1H_1-G_2H_2}$$

$$\dfrac{C}{R}=\dfrac{G_1+G_2(1-G_1H_1)}{1-G_1H_1}$$

$$\dfrac{C}{R}=\dfrac{G_1G_2}{1-G_1H_1}$$

$$\dfrac{1+G_1-G_1G_2}{1-G_1G_2}$$

$$\dfrac{1+G_1}{1-G_1G_2}$$

$$\dfrac{1+G_1G_2}{1+G_1+G_1G_2}$$

$$\dfrac{1-G_1G_2}{1+G_1-G_1G_2}$$

$$\dfrac{a^3}{(1-ab)^3}$$

$$\dfrac{a^3}{1-3ab+a^2b^2}$$

$$\dfrac{a^3}{1-3ab}$$

$$\dfrac{a^3}{1-3ab+2a^2b^2}$$

$$\dfrac{abcd}{1+ce+bcf}$$

$$\dfrac{abcd}{1-ce+bcf}$$

$$\dfrac{abcd}{1+ce-bcf}$$

$$\dfrac{abcd}{1-ce-bcf}$$

$$\dfrac{ab+c(1-d)}{1-d}$$

$$\dfrac{ab+c}{1-d}$$

$$\dfrac{ab+c(1+d)}{1-d}$$

$$\dfrac{ab}{1-d}$$

$$\vert G \vert = 1$$

$$\vert G \vert = 0$$

$$\vert G \vert = \infty$$

$$\vert G \vert = 0.707$$

$$\infty$$

0

0.1

1

$$(s+a)(s^2-s-0.1K)$$

$(s+a)(s^2-s-0.1K)$

$$\dfrac{K}{(s+a)(s^2-s-0.1K)}$$

$$\dfrac{K}{(s+a)(s^2+s-0.1K)}$$

$$\dfrac{G_1G_2+G_3}{1-(G_1H_1+G_2H_2)-G_3H_1H_2}$$

$$\dfrac{G_1G_2+G_3}{1-(G_1H_1-G_2H_2)}$$

$$\dfrac{G_1G_2-G_3}{1-(G_1H_1-G_2H_2)}$$

$$\dfrac{G_1G_2-G_3}{1-(G_1H_1+G_2H_2)}$$

$$\dfrac{d^2}{dt^2}c(t)+5\dfrac{d}{dt}c(t)+4c(t)=r(t)$$

$$\dfrac{d^2}{dt^2}c(t)-5\dfrac{d}{dt}c(t)-4c(t)=r(t)$$

$$\dfrac{d^2}{dt^2}c(t)+4\dfrac{d}{dt}c(t)+5c(t)=r(t)$$

$$\dfrac{d^2}{dt^2}c(t)-4\dfrac{d}{dt}c(t)-5c(t)=r(t)$$