Ten more than three times a number n is forty. How do you write this as an equation, plz i need help.

Carley bought a jacket that was discounted 10% off the original price. the expression below represents the discounted price in dollars, based on x, the original price of the jacket.

Could someone me with this question i’ve been stuck on it for 20 minutes

Solve the following: 12(x^2–x–1)+13(x^2–x–1)=25(x^2–x–1) 364x–64x=300x