If x = 3 and y = 5, work out the value of
b) 2x2 + 3y2

Is the open sentence 5x-2=3x+2 true when x=2? justify your answer.

In 2009, there were 1570 bears in a wildlife refuge. in 2010, the population had increased to approximately 1884 bears. if this trend continues and the bear population is increasing exponentially, how many bears will there be in 2018?

In triangle △abc, ∠abc=90°, bh is an altitude. find the missing lengths. ah=4 and hc=1, find bh.