Crosswords1 min ago
checking maths answers
Factor, and anyone else good at maths, i've done some stuff but can you check them please, I would get my mum or dad or friend to but; i lost mum and dad with most my work in year 9 and my friends are only doing foundation.
1) these are eqations of lines; (P) y=3x+5 (Q) y=4-3x (R) y+3x=1
a) which is parallel to y=3x ? P and Q
b) which goes through the point (2,7) ? S
c) write down the gradient of y+2x=7 ? +7 (is it necessary to say + ?)
And this at the start of a paper but i always find explaining things hard.
2) mike says that 18% or £840 is equal to 36% of £420
explain why he is correct, do not calculate 18% of £840.
18% is half of 36%. and 840 is double 420.
2 (n/2) = n ?????????? i have no idea if that is right.
3)make t the subject of the formula w=2t+v
-v . . . . . w-v=2t
1/2 . . . . (w-v)/2=t
when doing stuff liek that above, i normally draw a vertical line and and jot down my stages, similar to what i've done there, is that a good idea? When checking back over, its easier to spot mistakes i think and its clear to the examiner what i was doing.
1) these are eqations of lines; (P) y=3x+5 (Q) y=4-3x (R) y+3x=1
a) which is parallel to y=3x ? P and Q
b) which goes through the point (2,7) ? S
c) write down the gradient of y+2x=7 ? +7 (is it necessary to say + ?)
And this at the start of a paper but i always find explaining things hard.
2) mike says that 18% or £840 is equal to 36% of £420
explain why he is correct, do not calculate 18% of £840.
18% is half of 36%. and 840 is double 420.
2 (n/2) = n ?????????? i have no idea if that is right.
3)make t the subject of the formula w=2t+v
-v . . . . . w-v=2t
1/2 . . . . (w-v)/2=t
when doing stuff liek that above, i normally draw a vertical line and and jot down my stages, similar to what i've done there, is that a good idea? When checking back over, its easier to spot mistakes i think and its clear to the examiner what i was doing.
Answers
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For more on marking an answer as the "Best Answer", please visit our FAQ.Yes, always explain what you are doing. Write each step separately (many pupils just write an endless stream of nonsense calculations such as 1+1=2 x3=6 +100 =106
I suggest you 'tell a story' to the examiner about what you are doing (eg "subtracting v from both sides"), but in your case be careful as I know you can go on a bit sometimes, lol).
I suggest you 'tell a story' to the examiner about what you are doing (eg "subtracting v from both sides"), but in your case be careful as I know you can go on a bit sometimes, lol).
Mike says that 18% or £840 is equal to 36% of £420. Explain why he is correct; do not calculate 18% of £840.
Well you could say 18% of £840 = 840 x 18/100
840= 2 x 420
18 x 2 =36
so 18% of £840 = 840 x 18/100 can be rewritten as 2 x 420 x (36/2)/100
which in turn can be rewritten thus:
2 x 420 x (36/2)/100 = 420 x 36/100.
Now 36% of £420 = 420x 36/100
The two are identical.
But that's a bit long winded isn't it.
If it's worth only one mark I'd go for your explanation- they simply want you to show you know that y% of 2n is the same as 2y% of n
Well you could say 18% of £840 = 840 x 18/100
840= 2 x 420
18 x 2 =36
so 18% of £840 = 840 x 18/100 can be rewritten as 2 x 420 x (36/2)/100
which in turn can be rewritten thus:
2 x 420 x (36/2)/100 = 420 x 36/100.
Now 36% of £420 = 420x 36/100
The two are identical.
But that's a bit long winded isn't it.
If it's worth only one mark I'd go for your explanation- they simply want you to show you know that y% of 2n is the same as 2y% of n
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