Respuesta :

billiejean05

5) (x+2)(x+3)=12

  • Expand the brackets first.
  • x^2 + 5x + 6 = 12
  • now minus 12 from both sides to make it equal to zero
  • x^2 + 5x - 6 = 0
  • Factorise.
  • (x+6)(x-1)=0
  • x+6=0
  • x-1=0

x=-6

x=1

6) (x-2)^2 = 36

  • Expand.
  • (x-2)(x-2)
  • x^2 - 4x + 4 = 36
  • Minus 36 from both sides
  • x^2 - 4x - 32 = 0
  • Factorise.
  • (x-8)(x+4)=0
  • x-8=0
  • x+4=0

x=8

x=-4

8) x(x-2)=3

  • Expand.
  • x^2 - 2x =3
  • Minus 3 from both sides.
  • x^2 - 2x - 3 = 0
  • Factorise.
  • (x-3)(x+1)=0
  • x-3=0
  • x+1=0

x=3

x=-1

9)3x(x+1)=5

  • Expand.
  • 3x^2 + 3x = 5
  • Minus 5 from both sides.
  • 3x^2 + 3x - 5 = 0
  • You can't factorise, so use the quadratic formula.

[tex]x = \frac{ - 3 \frac{ + }{ - } \sqrt{ {3}^{2} - 4(3 \times - 5) } }{2 \times 3} [/tex]

Your answers should come out to be:

x= 1.88(to 2 d.p.)

and

x= -0.88(to 2 d.p.)

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