PL HEL Subtract 6/7-3/x

Two sides of a triangle mesure 20cm and 30cm. what is the measure of the third side

The marked price of an article is 25% above its selling price and the cost price is 30% less than its marked price . find the discount percent and gain percent. only a brainlest can solve it i will mark you brainlest

Check all that apply. f is a function. f is a one-to-one function. c is a function. c is a one-to-one function.