2/1 over 1/5 is equal to and 3/4-5/9 and 1 1/2+2 3/7 also 2/3÷3/6 and 3 1/2×1 3/7 Please help​

Express in the simplest form: (x^2+9x+14/x^2-49) / (3x+6/x^2+x-56)

Given: klmn is a parallelogram m? n=3m? k, lf ? kn , ld ? nm kf=2 cm, fn=4 cm find: lf, ld

Acomputer store buys a computer system at a cost of $370.80. the selling price was first at $ 618, but then the store advertised a 20 % markdown on the system. answer parts a and b. a. find the current sale price.