Please help I'm really struggling here! Work out and estimate the mean time it took the students. Round your answer to 2 significant figures.

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

What is the solution to this system of equations? y= 2x - 3.5 x - 2y = -14

Jayne is studying urban planning and finds that her town is decreasing in population by 3% each year. the population of her town is changing by a constant rate. true or false?