Answers − Quadratic Graphs using x and y axis − 2
1. Draw the graph y = 2x2 + 10x + 8
| (a) The graph crosses the y axis at the number term c which is 8. When x = 0 then y = 8. The coordinate is (0, 8) |
| (b) The graph crosses the x axis where 2x2 + 10x + 8 = 0. Refer to question 1 of Solve Quadratics by Factorising - 2. So y = 0 when x = −4 or −1. The coordinates are (−4, 0) and (−1, 0) |
| (c) Draw the graph using the above coordinates |
2. Draw the graph y = 3x2 + 21x + 18
| (a) The graph crosses the y axis at the number term c which is 18. When x = 0 then y = 18. The coordinate is (0, 18) |
| (b) The graph crosses the x axis where 3x2 + 21x + 18 = 0. Refer to question 2 of Solve Quadratics by Factorising - 2. So y = 0 when x = −6 or −1. The coordinates are (−6, 0) and (−1, 0) |
| (c) Draw the graph using the above coordinates |
3. Draw the graph y = 4x2 + 20x − 24
| (a) The graph crosses the y axis at the number term c which is −24. When x = 0 then y = −24. The coordinate is (0, −24) |
| (b) The graph crosses the x axis where 4x2 + 20x − 24 = 0. Refer to question 3 of Solve Quadratics by Factorising - 2. So y = 0 when x = −6 or 1. The coordinates are (−6, 0) and (1, 0) |
| (c) Draw the graph using the above coordinates |
4. Draw the graph y = 2x2 + 9x − 56
| (a) The graph crosses the y axis at the number term c which is −56. When x = 0 then y = −56. The coordinate is (0, −56) |
| (b) The graph crosses the x axis where 2x2 + 9x − 56 = 0. Refer to question 4 of Solve Quadratics by Factorising - 2. So y = 0 when x = −8 or 7/2. The coordinates are (−8, 0) and (7/2, 0) |
| (c) Draw the graph using the above coordinates |
5. Draw the graph y = 5x2 − 20x − 60
| (a) The graph crosses the y axis at the number term c which is −60. When x = 0 then y = −60. The coordinate is (0, −60) |
| (b) The graph crosses the x axis where 5x2 − 20x − 60 = 0. Refer to question 5 of Solve Quadratics by Factorising - 2. So y = 0 when x = −2 or 6. The coordinates are (−2, 0) and (6, 0) |
| (c) Draw the graph using the above coordinates |
6. Draw the graph y = 3x2 − 21x + 36
| (a) The graph crosses the y axis at the number term c which is 36. When x = 0 then y = 36. The coordinate is (0, 36) |
| (b) The graph crosses the x axis where 3x2 − 21x + 36 = 0. Refer to question 6 of Solve Quadratics by Factorising - 2. So y = 0 when x = 3 or 4. The coordinates are (3, 0) and (4, 0) |
| (c) Draw the graph using the above coordinates |
7. Draw the graph y = 3x2 − 40x + 48
| (a) The graph crosses the y axis at the number term c which is 48. When x = 0 then y = 48. The coordinate is (0, 48) |
| (b) The graph crosses the x axis where 3x2 − 40x + 48 = 0. Refer to question 7 of Solve Quadratics by Factorising - 2. So y = 0 when x = 4/3 or 12. The coordinates are (4/3, 0) and (12, 0) |
| (c) Draw the graph using the above coordinates |
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