Another few GCSE questions, help, these are for revision...?

Question

Please help, i need to know how to do these, so i can revise them...

Solve the simultaneous equation:
y=x+2
y=3x(to the power 2)

Work out the value of:
3f(to the power 2) - 4t +1 when t= -1
and: 2x (to he power minus one-third) when x=8

Mary lost her calculator and had to work out [64(to the power 2)] (to the power one-third).
How could she work it out mentally?

Simplify fully : 5(square root 2) + square root of 8

Write (square root 6)*(square root 3) in the form a(square root b), where a and b are prime.

Please help me, if u can answer any, i wud be grateful! Thanx...

How about you stop wasting ur time and mine, putting stupid answers up... Thank u very much. And its isnt homework, so there you go... Just want help on questions in a revision book... Cant i get help around here without weirdos having a go...

Thats the point, their in a revision guide... im askin for help n if u doint wanna answer them, please dont have a go...

Seriously... will people stop asking me to ask someone else... this is extra stuff... n i want help not advice... :( WILL NO ONE HELP... Im aiming for an A thanx, but these are hard questions... if no one wants to help then fine...

Answer 1

!) similutaneos equations. All you have to do is make the same thing the subject of the equation and as they both say y= you dont have to do anything about that. AS they both =y that means they equal each other to so you put
x+2 = 3xsquared.
next you need all the variables (ie x or xsquared) on one side so you get:
2=3xsquared - x
this gives you a quadratic equation:
0=3xsquared -x-2
im not so good at explaining quadratics but basically they are (x +?) (x-?) and the two questionmarks multiply to make -2 and they have a difference of -1 -because its only -1 x.
this works out as (3x +2)(x-)
and you cant really solve it becuse you have 2 variables.

2) you wont be able to work this one out unless you have a value that that equals if you get what i mean. You need an equals sign. or a value for f.
as for the 2nd part, when something is to the power of minus something its like putting it as a fraction 1 over. so it'd be 1/8(and the 8 would be to the power of 1/3)
If you think about that, 8 is the cube of 2. so it could be 1/2cubed and then to the power of a third. These cancel out so you have 1/2 or a half.

3)what you want if for the indicie inside the bracket to be a 3 not a two. because then it will cancel out the 1/3 on the outside. as it happens, 64 is 8squared so it can be (8cubed)to the power of 1/3. this makes it equal 8.

4)these are surds. the squared root 8 could be square root 4 and square root 2. or 2 tyimes squared root 2. when added to the 5 square root 2 this makes 7 square root 2. this, if all changed to surds, is square root 98.

5)when two surds are multiplied, you can multiply the numbers and make it into one surd (ie square root 6 x square root 3 is square root 18). If you find the factors of this, you can get 9 and 2, which when multiplied make 18. therefore square root 18 = square root 2 x square root 9 or square root 2 times 3. rearrange this and you have your answer 3(square root 2)

I hope i have helped and i wish you luck in all your GCSEs, I have mine soon too.

Answer 2

These hints should help

1) substitute the second equation into the first then solve using the quadratic formula.

2) not sure what f is, I assume this is a typo. Just substitute the values into the equations. The 2x (to he power minus one-third) means 2 * (1 divided by the cube root of x)

3) 64 is a power of 2 number (2 to the power 6 = 64)
so 64 (to the power 2) = 2 (to the power 12)
so [64(to the power 2)] (to the power one-third) = 2 (to the power 4)

4) square root of 8 = 2 * square root 2

5) (square root 6) = (square root 2) * (square root 3)
so (square root 6)*(square root 3) = 3 * (square root 2)


good luck

Answer 3

They're good grades, and your Maths and Science grades are what's really important for medicine, and you did well. Incidentally - don't take what your parents say to heart. You got 3 A*s, 6 As, 2 Bs and a C. When I took my GCSEs, I got 6 As, 3 Bs and 2 Cs. So you did better than I did. And I went on to get AAB in my A levels, and am now studying for a degree at a university that's one of the best in the country for my course. So don't worry, don't be disappointed, and don't give up hope. With regards to English Lit - the Lit A level is pretty difficult, so perhaps with a C you might struggle. But have you considered taking English Language? In my opinion, it's a more interesting course. That said, if you want to do medicine, you really do need to take Physics and/or Maths.

Answer 4

(1) y = x+2 = 3x => x+2 -3x = 0
-2x +2 = 0
2(1-x) = 0
1 -x = 0
x = 1

(2) 3(-1) -4(-1) +1 = -3 +4 +1 = 2

(3) 2(8)^(-1/3) = 2/(8)^(1/3) = 2/2 = 1

(4) (64^2)^(1/3) = (64^(1/3))^2 = (4)^2 = 16

Note: Let sqrt(x) denote "square root of x."

(5) 5*sqrt(2) +sqrt(8) = 5*sqrt(2) +sqrt(4*2)
= 5*sqrt(2) + sqrt(4)*sqrt(2)
= 5*sqrt(2) + 2*sqrt(2)
= (5+2)*sqrt(2)
= 7sqrt(2)

(6) sqrt(6)*sqrt(3) = sqrt(6*3)
= sqrt(18)
= sqrt(9*2)
= sqrt(9)*sqrt(2)
=3*sqrt(2)

]This is in the form a*sqrt(b) where a and b are prime.

Answer 5

This is easy:

you should be ace at these by the time u go ur gcse in JUNE!!!

for the first one, make them equal each other as they both equal y.

move everything over reversing the signs as usual, then factorise like a stnadard quadratic.

Answer 6

Ask your maths teacher and pc's come with calculators. Also on the higher maths papaer you only need to get 30 right out of the 2 papers to get a C

Answer 7

figure it out yourself, otherwise you'll never learn anything. buy a revision guide

Answer 8

G.C.S.E seems alot harder these days!

but got on you, comin on here for help

Answer 9

dnt u have a brain hahahaha

Answer 10

http://www.mathsleague.com