O-Level Additional Math

[htn]

Hi


Please help.

Secondary Two Maths.

Factorise

1)2r^2-5r-3

Expand and simplify the following expressions
1)(a+b)^2 - (a-b)^2

2)(x+2y)(x-6y)- (x-3y)(x-y)

TIA

[koguma]

htn:

Hi


Please help.

Secondary Two Maths.

Factorise

1)2r^2-5r-3

Expand and simplify the following expressions
1)(a+b)^2 - (a-b)^2

2)(x+2y)(x-6y)- (x-3y)(x-y)

TIA

This is basic algebra which is taught in Sec 1. Hope you understand the steps.

1)2r^2-5r-3
= (2r+1) (r-3)

Note : for the 2 qns below, since outside bracket the sign is \"-\", when you remove bracket you must change the sign of all terms inside the bracket

2)(a+b)^2 - (a-b)^2
Use (a + b) ^2 = a^2 + 2ab + b^2
Use (a − b) ^2 = a ^2 − 2ab + b ^2

(a+b)^2 - (a-b)^2
= a^2 + 2ab + b^2 – (a ^2 − 2ab + b ^2)
= a^2 + 2ab + b^2 – a ^2 + 2ab - b ^2
= 4ab

3)(x+2y)(x-6y)- (x-3y)(x-y)
= x^2 -6xy+2xy-12y^2 – [x^2 –xy-3xy+3y^2 ]
= x^2 -6xy+2xy-12y^2 – x^2 +xy + 3xy -3y^2
= -15y^2

[kuts]

Hi, Can anybody help solve this problem. Very urgent. Thanks in advance



Marks\t 0\t1\t2\t3\t4
No pupils\t2\t1\t3\t1\tP

Find the value of p if the median is 2.5 marks

[Skyed]

kuts:

Hi, Can anybody help solve this problem. Very urgent. Thanks in advance



Marks\t 0\t1\t2\t3\t4
No pupils\t2\t1\t3\t1\tP

Find the value of p if the median is 2.5 marks

P = 5

[kuts]

Skyed:

kuts:

Hi, Can anybody help solve this problem. Very urgent. Thanks in advance



Marks\t 0\t1\t2\t3\t4
No pupils\t2\t1\t3\t1\tP

Find the value of p if the median is 2.5 marks

P = 5

Thanks, btw, could u please explain me

[Skyed]

kuts:

Skyed:

[quote=\"kuts\"]Hi, Can anybody help solve this problem. Very urgent. Thanks in advance



Marks\t 0\t1\t2\t3\t4
No pupils\t2\t1\t3\t1\tP

Find the value of p if the median is 2.5 marks

P = 5

Thanks, btw, could u please explain me[/quote]Hi, median is the middle mark. Assuming you take 2.5 as a mark on it's own, the number of students who got 0, 1, 2, and 2.5 is a total of 7. Then because you need 2.5 to be the number in the middle, the number of people who got 3 marks, 4 marks and the 2.5 mark has also to be equal to 7. Therefore, 7 -1 -1 = 5.

To double check, you can add up all the values (2+1+3+1+5) = 12 and then +1 = 13 divided by 2 to find the median, which is 2.5.

[kuts]

Can anybody help solve this statistical question


No\t0\t1\t2\t3\t4\t5\t6
Pupils\t3\t8\t11\t8\t6\t3\t1

Find Mean, median and mode of the distribution

[Skyed]

kuts:

Can anybody help solve this statistical question


No\t0\t1\t2\t3\t4\t5\t6
Pupils\t3\t8\t11\t8\t6\t3\t1

Find Mean, median and mode of the distribution

Mean: Add everything up, divide by number of pupils.
Median: Find the middle number, just add all the pupils + 1 divided by 2.
Mode: The one with the most number of pupils.

Please try the questions first at least before just posting without even attempting ._. Mode is the easiest thing to find, and so is mean.

[katherina]

how to solve using quadratic formula. Help please!

5(x² +4)=12x

[koguma]

katherina:

how to solve using quadratic formula. Help please!

5(x² +4)=12x

step 1: remove the bracket by multiply 5 into the all the terms inside the bracket
step 2: move 12x from RHS to LHS

5(x² +4)=12x
5x² + 20 = 12x
5x² + 20 - 12x = 0

Stop here, try to solve from here. if hit problem do post then i will continue