some math questions?

Question

ok, so i have a huge maths test tomorrow and ive been given this easy revision sheet to refresh my memory on the basics.. but ive completely forgotten everything [its like midnight]

so heres my Qs, if someone could help me out id apreciate it =]

x(x-2)=0
(3x-1)²=0
x²/3=3
x²-3x=0
x²-6x-7=0
(x+6)(x-3)= -14
x²+6x-7=0


thank you everyone!! =D i dont really want to cheat, so if you could just give me some pointers or clues or what ever that would be cool

Answer 1

ok,here you are required to find the value(s) of x..

x(x-2)=0

in multiplication,anything into zero is zero right?so here the same..

so x could be zero or (x-2) is..

therfore,

x=0 or x-2=0
so the final answer is,
x=0 or x=2

------------------------------------------------------------------------------------
(3x-1)²=0
(3x-1)(3x-1)=0
same goes here..
3x-1=0
3x=1
x=1/3
------------------------------------------------------------------------------------
x²/3=3
we multiply the equation througout by 3 as to cancle the /3..
so,
x²=9
x=3 or -3
------------------------------------------------------------------------------------
x²-3x=0
x(x-3)=0
again the same..
x=0 or x=3
------------------------------------------------------------------------------------
x²-6x-7=0
(x+1)(x-7)=0 <-- im sure you can do this..
(x+1)=0 or (x-7)=0
so,
x=-1 or x=7
------------------------------------------------------------------------------------
(x+6)(x-3)= -14
x²+3x-18=-14
x²+3x-4=0
(x-1)(x+4)=0
x=1 or x=-4
------------------------------------------------------------------------------------
x²+6x-7=0
(x-1)(x+7)=0
x=1 or x=-7

ok,i hope you pass your HUGE test...hehe.

Answer 2

You need to make sure all the equations are equal to Zero. Then you can factorise and solve them. If you end up with two brackets for example: (x - 3) (x +6) then x must be equal to either 3 or -6 to make one of the brackets a zero value, which in turn makes the whole sum a zero value.

I've done these for you.....

1) x=0 or x=-2

2) x= 1/3

3) x= 1

4) x= 0 or x= -3

5) x= -1 or x= 7

6) x= -4 or x= 1

7) x= 1 or x= -7

Answer 3

x(x-2) = 0
or, x-2 = 0 (since I'm dividing the 0 with x)
or, x =2

(3x-1)2 = 0
or, (3x-1)(3x-1)= 0
or, (3x-1)= 0
or, x = 1/3

x2/3 = 3
or, x2 = 9
or, x =3

x2-3x= 0
or, x(x-3) = 0
or, x-3 = 0
or, x= 3

x2-6x-7 =0
(using middle term factorisation, factorise the left hand side)
or, x2 -7x+x -7=0
or, x(x-7) + 1(x-7)=0
or, (x-7) (x+1) =0
Now either (x-7)=0 OR (x+1)=0
When (x-7)=0, x=7
When (x+1)= 0, x= -1
Therefore, x= 7 or -1

(x+6)(x-3) = -14
or, x2 - 3x +6x- 18 = -14
or, x2+ 3x -18 +14= 0
or, x2 + 3x -4 =0
or, x2 +4x -x -4 =0
or, x(x+4) -1(x+4)=0
or, (x-1)(x+4) =0
Now either (x-1)=0 or (x+4)=0
When (x-1)= 0, x=1
When x+4= 0, x= -4
Therefore, x= 1 or -4

x2+ 6x -7 = 0
or, x2 + 7x - x -7 =0
or, x(x+7) -1(x+7) = 0
or, (x-1)(x+7) =0
Now either (x-1) = 0 or (x+7)=0
When (x-1)=0, x=1
When (x+7)= 0, x= -7
Therefore, x= 1 or -7

NB- These sums are quadratic equations

Answer 4

x=0 or x=2

3x - 1 = 0 x=1/3

x^2 = 9, so x=3 or x= -3

x(x-3)=0 x=0 or x=3

(x - 7)(x +1) = 0, so x=7 or x= -1

x^2 + 3x - 18 = -14, so x^2 + 3x -4=0
(x+4)(x-1)=0 x= -4 or x= 1

(x+7)(x-1) = 0, so x= -7 or x=1

Answer 5

sry i help u coz school work must be done by urself