In paragraph 2, the narrator says, "As simple as the ride seems, only advanced engineers can make safe and fun Feris wheels." Can you think of any other machines that seem simple but actually are not? List at least two and explain why they are not actually simple.

substitute y = 2x - 4 to x + 2y = 12:

x + 2(2x - 4) = 12     use distributive property

x + (2)(2x) + () = 12

x + 4x - 8 = 12     add 8 to both sides

5x = 20     divide both sides by 5

x = 4

put the value of x to the first equation:

y = 2(4) - 4

y = 8 - 4

y = 4

what passage are you referring to