PLS HELP MARKING BRAINLIST QUESTION BELOW

Simplify 15(x - 4)(x -1)-3(x + 4)(x - 1) with steps

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

If a 36 inch yardstick casts a 21 foot shadow, how tall is a building whose shadow is 168 feet? what is the scale factor