Question

Please help!!! How do you solve 5,6,8 and 9?

Answer 1

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.

`x = \frac{ - 3 ( + )/( - ) \sqrt{ {3}^(2) - 4(3 * - 5) } }{2 * 3}`

Your answers should come out to be:

x= 1.88(to 2 d.p.)

and

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