Algebra Flashcards
(8 cards)
How do you factorise quadratic with only one x2?
Write in the brackets, with an x on each side. Then figure out the two numbers that will add to make the middle number, and times to make the end number. Make sure the signs are right.
What is DOTS and how do you do it?
It is when two number look like a2 - b2. It always factorises to look like (√a+√b) (√a-√b).. An example is 4x2 - 16. It will go to (2x+4) (2x-4).
How do you square brackets?
You times the bracket by itself, then expand it as normal. E.g ( a +3)2. This goes to (a+3) (a+3), then a2 + 3a +3a +9.
How would you work an equation like this: (a+3)2 + (a+1)(a-2)?
First square the squared bracket as we learnt. (A+3)(a+3) + (a+1)(a-2). Then you can multiply each pair of brackets together. A2+3a+3a+9 + a2-a-2. You can then collect all the like terms to get 2 a2 + 5a +7.
How do you expand quadratic brackets?
Times everything in one bracket by everything in the other, use the lobster claw method
How do you solve quadratic equations by factorising?
Ensure there is a 0 on one side, you may need to do some rearranging. Then factorise the equation. The numbers in the brackets equal x when their signs are flipped round.
How do you draw quadratic graphs?
Fist work out if it is n or u, by looking to see if it’s a - or + x^2. Plot several points, using different values of x, using the equation to find y. Then you can join up the points to make the curve
How do you use quadratic graphs to solve equations?
Rearrange the equation so you have the equation of the line on one side. If there is a single number on the other side, look at that line on the y axis, and where it crosses the line you drew are the two answers. If there is another equation on the other side, draw that line and see where they intersect to get the two answers.
