Perform the operation.
(4x^2+9x-7)-(-7x^2+5x-1)

David bought a poster for an art project. the poster is 2.7 feet wide and 3.9 feet tall. what is the area of the poster?

Apatient is given 50 mg dose of medicine the medicines effectiveness decreases every hour at a constant rate of 40% what is the exponential decay function that models this scenario how much medicine will be left in the patients system after 2 hours

What is the answer to this question? i'm a bit stumped. also how do i do it? 5(x - 4) = 2(x + 5)