1. 3(x + 2) + 5 = 2x – (1 + 3x) 3x + 6 + 5 = 2x – 1 – 3x 3x + 11 = -x – 1 4x + 11 = -1 4x = -12 x = -3 3(x + 2) + 5 = 2x – (1 + 3x) 3x + 6 + 5 = 2x – 1 + 3x 3x + 11 = 5x – 1 11 = 2x -1 12 = 2x x = 6 3(x + 2) + 5 = 2x – (1 + 3x) 3x + 6 + 5 = 2x – 1 – 3x 6 + 5 = 2x - 1 - 6x 11 = 4x - 1 12 = 4x x = 3 Two of the solutions below have common mistakes in them, only one is correct. Find the two common mistakes Explain why they are so common and their effect Discuss how you can avoid these mistakes

2. Study the two solutions below. Which of them is correct? Where are any errors? Are these errors common? How could they be avoided? Would you lay things out differently? Mark stands 27 metres from the base of the Eiffel Tower as shown. He needs to look up at an angle of 85∙24 o to look directly at the top. How tall is the Eiffel Tower (to the nearest metre)? 27m 85.24 o 27m 4.76 o Tan 4∙76 o = 27 x 27 tan 4∙76 o = x x = 2∙25m 27m 85.24 o Tan 85∙24 o = x 27 27 tan 85∙24 o = x x = 12m x = 11∙96038166 Tan x o = opp adj SOH CAH TOA

3. 0.2, 0.52, 0.025, 0.052, 0.520, 0.505, 0.5555 Study the four solutions below. Three of them are incorrect. Which three? Explain why the three wrong answers are wrong. What could someone writing these be thinking? Put these decimals in order, smallest first: 0.505, 0.52, 0.052, 0.55555, 0.520, 0.025, 0.2 0.2, 0.025, 0.052, 0.52, 0.520, 0.505, 0.5555 0.025, 0.052, 0.2, 0.505, 0.52, 0.520, 0.5555 0.025, 0.052, 0.505, 0.520, 0.2, 0.52, 0.5555