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Algebra.

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Presentation on theme: "Algebra."— Presentation transcript:

1 Algebra

2 Collecting Terms This is a way of simplifying algebra
If you have b + b + b + b This is the same as 4 b The b could stand for boots If you have p x p x p This is p3 This happens when multiplying

3 Try these: M x m T + t + t R x r x r x r G + g + g + g H x h x h K + k
J x j x j x j x j x j x j

4 Answers M2 3t R4 4g H3 2k j7

5 Collecting terms Usually you have to collect terms from a mix
You cannot add 2t and t2, you can only add t2 and t2 together E.g. A2 + 3a + 3a + 2a2 3a + 3a = 6a A2 + 2a2 = 3 a2 So the simplified equation is 6a + 3 a2

6 Collecting terms You may have to deal with minus numbers or terms
Always look at the sign before the term to see if it is positive (+) or negative (-) E.g This is +3 and -1 and -4 3 -1 = 2 2 - 4 = -2

7 Now try these; -5 +4 -3 3h + 2h – 6h 3s + 3s – 8s 7y – 5y – 2y
3d – d + 2d – 5d 7r – 4r – 5r -2r 5p – p + 3p – 2p

8 Answers -4 -1h or -h -2s -1d or –d -4r 5p

9 Mixed terms J + j + k + k + k R – 2r +3s +2s 7y – 5y – 3y +4
3t + 6s – 8s + t 7r + 2s – r – s 5p + 6 – 7p – 9 3a + b + a - 2b

10 Answers 2j + 3k -r + 5s -y + 4 4t – 2s 6r + s -2p – 3 4a - b

11 Multiplying Terms When you multiply terms you multiply the numbers at the start of the term and then add together the number of letters you have E.g. 2a x 3a This is 2 x 3 = 6 And a x a = a2 This is 6a2

12 Multiplying 2 x 4c 2 x r x s 5 x 3c 2e x 6e 3a x 2a (4k)2 4r x 2rs

13 Answers 8c 2rs 15c 12e2 6a2 16k2 8r2s

14 Try these 5ab – 3ab 6vw – 4w + 5wv X + 2x – 3x2 + 5x2
8r + 6rs – 2sr – 3r Xy + x2 – 3xy + 3x2 4y + 3y2 – 7y2 – 2y

15 Answers 2ab 11 vw + 4w 3x + 2x2 5r – 4rs -2xy + 4x2 2y – 4y2

16 Multiplying Out Brackets
Everything inside the brackets is multiplied by the term just outside it to the left E.g. 4 (3 + t) This is 4 x 3 = 12 And 4 x t= 4t So it becomes t

17 Try these 6(1-s) 4(p + q) 3(10j-4k) R2(3-2s) 2x3 (x-y) 5t2 (s + t)
3r (2r – 3s – t)

18 Answers 6 -6s 4p + 4q 30j + 12k 3r2 + -2r2s 2x4 – 2x3y 5st2 + 5t3
6r2 – 9rs – 3rt

19 Factorising This is the opposite of multiplying out brackets
When you simplify you can place terms inside brackets E.g. 4k + 2 Both can be divided by 2 So it becomes 2(2k + 1) Everything inside the bracket is divided by 2

20 Try these 3f + 3 15 + 20 t 18 + 6a 10j + 25 3r + 3s + 3t Pq – q2
24p2 + 30pq 20ab2 + 36a2b2

21 Answers 3 (f + 1) 5 (3 + 4t) 6 (3 + a) 5 (2j + 5) 3 (r + s + t)
Q (p – q) 6p (4p + 5q) 4ab (5b + 9ab)

22 Multiplying Brackets with -
If there is a minus before the brackets A minus x a plus = a minus A minus x a minus = a plus E.g. -3(2r – r) -3 x 2r= -6r -3 x –r = +3r So it becomes -6r + 3r

23 Try these -8(s-t) -(r-5) -(4r-3) -9y(y-1) -5s(s+4) -3h(5-h) - (x+y)

24 Answers -8s + 8t -r + 5 -4r + 3 -9y2 + 9y -5s2 + 20s -15h + 3h2 -x - y

25 Multiplying sets of brackets
If you are given 2(3+y) + 5(4+y) First you must multiply out the brackets 6 + 2y y Secondly you collect terms 26 + 7y

26 Try these 3(4+d)+4(2+d) 6(3+x)+5(2-x) 2(10+5e)-3(6+e) 3(4r+1)-(7r-2)
4(w+1)-(w-1) X(2x+1)+2(3x+4) 4(5+2f)+f(3+f)

27 Answers 20 + 7d 28 + x 2 + 7e 5r + 5 3w + 5 2x2 + 7x + 8 f + f2

28 Multiplying out brackets
If you are given (y+2)(y-4) Then you really have two sums Y(y-4) +2 (y-4) We have split the first bracket up to make sure we multiply everything together So what do they workout as; Y2 – 4y +2y -8 We need to collect the terms -4y + 2y = -2y So the equation is y2 -2y -8

29 Try these (s+1)(3s+2) (2+f)(1+4f) (d-2)(3d+5) (7+k)(1+k) (a+3)(4a-1)
(y-2)(y+2) (a+b)(a-b)

30 Answers 3s2+5s+2 2+9f+4f2 3d2-d-10 7+8k+k2 4a2+11a-3 Y2-4 A2-b2

31 (Brackets)2 If you have (4g+h)2 This means (4g+h) )(4g+h) First we …
Split up the first bracket 4g(4g+h) +h(4g+h) 2. Then we multiply this out 16g2 + 4gh +4gh + h2 3. Then we collect terms +4gh + 4gh = +8gh So our equation is 16g2 + 8gh + h2

32 Solving Equations If you have a number and no x2 or x3 you can solve a linear equation E.g. 4x=16 X = 16/4 X= 4 x/7=-2 Multiply both sides by 7 X = -14 What you do to one side of the equals sign you must do to the other to keep everything balanced

33 Try these x/5= 12 X-7=23 X + 12 = 45 0.5x=3 2x/3 = -6 x/3 + 2 =10

34 Answers X= 60 X= 30 X= 33 X= 6 X= -9 X= 24 X= 7

35 Solving Equations You should always try to keep x positive, so work from the side with the most x’s E.g. 2x + 17= 4x We need to take 2x away from both sides 17 = 2x 8.5 = x

36 Harder questions 13x-15 = 12x+19 2.5x + 10 = 1.5x + 17 12x-1 = 7x+19

37 Answers X= 34 X= 7 X= 4 X= 3 X= 1 X= 2

38 Changing the Subject Sometimes you have to rearrange equations E.g.
C= a – b I want to find out what a equals If I add b to both sides I have a on it’s own C + b = a

39 Try these T= sk - h V=u + at M=k + nk T2 = 7r + x/4 H= y/4 T= s2 + 5
A=π r2 S= ½gt2

40 Answers T/s + h/s = k v/a – u/a = t m/k– k/k = n T2/7- x/4/7 = r
4h = y √t-5 = s √a/ π = r √2s/g= t


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