$\text{327:}$

$A=\dfrac{1}{1.2}+$$\dfrac{1}{2.3}+$$\dfrac{1}{3.4}+....+$$\dfrac{1}{49.50}$

$A=1-\dfrac{1}{2}+$$\dfrac{1}{2}-$$\dfrac{1}{3}+$$\dfrac{1}{3}-$$\dfrac{1}{4}+....+$$\dfrac{1}{49}-$$\dfrac{1}{50}$

$A=1-\dfrac{1}{50}$

$A=\dfrac{49}{50}$

$B=\dfrac{2}{3.5}+$$\dfrac{2}{5.7}+$$\dfrac{2}{7.9}+...+$$\dfrac{2}{37.39}$

$B=\dfrac{1}{3}-$$\dfrac{1}{5}+$$\dfrac{1}{5}-$$\dfrac{1}{7}+$$\dfrac{1}{7}-$$\dfrac{1}{9}+....+$$\dfrac{1}{37}-$$\dfrac{1}{39}$

$B=\dfrac{1}{3}-$$\dfrac{1}{39}$

$B=\dfrac{12}{39}$

$B=\dfrac{4}{13}$

$C=\dfrac{3}{4.7}+$$\dfrac{3}{7.10}+$$\dfrac{3}{10.13}+....+$$\dfrac{3}{73.76}$

$C=\dfrac{1}{4}-$$\dfrac{1}{7}+$$\dfrac{1}{7}-$$\dfrac{1}{10}+....+$$\dfrac{1}{73}-$$\dfrac{1}{76}$

$C=\dfrac{1}{4}-$$\dfrac{1}{76}$

$C=\dfrac{9}{38}$

$\text{328:}$

$x+\dfrac{4}{5.9}+$$\dfrac{4}{9.13}+$$\dfrac{4}{13.17}+...+$$\dfrac{4}{41.45}=$$\dfrac{-37}{45}$

⇔ $x+(\dfrac{4}{5.9}+$$\dfrac{4}{9.13}+$$\dfrac{4}{13.17}+...+$$\dfrac{4}{41.45})=$$\dfrac{-37}{45}$

⇔ $x+\dfrac{1}{5}-$$\dfrac{1}{9}+$$\dfrac{1}{9}-$$\dfrac{1}{13}+$$\dfrac{1}{13}-$$\dfrac{1}{17}+....+$$\dfrac{1}{41}-$$\dfrac{1}{45}=$$\dfrac{-37}{45}$

⇔ $x+\dfrac{1}{5}-$$\dfrac{1}{45}=$$\dfrac{-37}{45}$

⇔ $x=\dfrac{-37+1-9}{45}$

⇔ $\text{x= -1}$