*extra points* can someone explain how to graph y= 2x - 1 ?

The -1 in the equation means that the y intersept is (0,-1) on the y axis. The 2x means the slope is 2 and the next point would be 2 points up and 1 point over because of the 2/1 or 2.  Your next point form the y-intercept would be (1,1) the (3,2) and so forth.

the answer for the second equation is (4,0)

we need to divide the number of toy dinosaurs, 156, by the number of brothers, 4:

in order to estimate, we can use compatible numbers:

156 ÷ 4

  ↓

160   ÷ 4 = 40        

the correct answer is a).