Week 6 Developing and Applying the Quadratic Formula

x^2 – 6x + 4=0

For me, quadratic formula is the easiest problem to solve because the only way to solve this is to remember the formula, and put each pattern in the foumula. Firstly, we need to find a, b and c for this formula in this question. A = 1, b= -6, c=4. Secondaly,  is to find the formula: .   Finally, place each pattern in  the formua.

We can get that:       The next important thing is that: do not forget to simplify (if it is possible) the last answer.

Week 5 Factoring Polynomial Expressions

x^2 -11x +30

=(x-5) (x-6)

Before solving this type of question, we should remind ourselves  of the ‘CDPEU’ chart, then find the right direction for solving this kind of question. According to the chart, this question is a trinomial one. The first part(x^2) and the last part(30) always provides informtaion. For example, if we want to find the factor of this one, we need to look at the first part and the last part. The last part is 30.  30=3 × 10=2×15=5×6, the middle part is -11x. Due to -11, we can eliminate 3&10, 2&15 becasue regardless of adding or substracting,  3&10 or 2&15 still can not get the answer of 11. There is only answer: 5&6 becasue 5+6=11, but there is one  thing very important is that the number is -11(it’s negative). The last part is a postive 30, so the final answer is -5&-6.