O-Level Additional Math

[beauty queen]

can u pls help me to solve this problem…


Given that(5x^3-4x^2+6x-2)=(x+3)(x-4)Q(x)+Ax+B where Q(x) is a polynominal, find the value of A and of B

Thank you

[beauty queen]

can u pls help me to solve this problem…


Given that(5x^3-4x^2+6x-2)=(x+3)(x-4)Q(x)+Ax+B where Q(x) is a polynominal, find the value of A and of B

Thank you

[beauty queen]

anyone can u pls help me to solve this problem..


Given that(5x^3-4x^2+6x-2)=(x+3)(x-4)Q(x)+Ax+B where Q(x) is a polynominal, find the value of A and of B

Thank you :thankyou:

[Xiao Hu]

beauty queen:

can u pls help me to solve this problem..


Given that(5x^3-4x^2+6x-2)=(x+3)(x-4)Q(x)+Ax+B where Q(x) is a polynominal, find the value of A and of B

Thank you

Try substituing x=-3 and x=4 into the equation. These values of x come from trying to make the factors of (x+3) and (x-4) to become zeros, so that we don't have to worry about Q(x) as that part of the expression becomes 0. Then you would obtain 2 equations with A and B, which should be able to solve.

Regards,
Xiao hu.

[dazzlego]

beauty queen:

anyone can u pls help me to solve this problem..


Given that(5x^3-4x^2+6x-2)=(x+3)(x-4)Q(x)+Ax+B where Q(x) is a polynominal, find the value of A and of B

Thank you :thankyou:

Hi beauty queen,

There are 2 ways to solve this question.

1. Using Remainder Theorem
If the polynomial f(x) is divided by (ax-b), the remainder is f(b/a)

In this case, f(x) is (5x^3-4x^2+6x-2)
And when f(x) is divided by (x+3) or (x-4), the remainder will be Ax+B.

In other words, f(-3) = -3A+B and f(4) = 4A+B
f(-3) = 5*(-27) - 4*9 + 6*(-3) - 2 = - 191
f(4) = 5*64 - 4*16 + 6*4 - 2 = 278

-3A + B = -191
4A + B = 278
Solve the simultaneous equations to get A=67 and B=10

2. Using Long Division
Divided (5x^3-4x^2+6x-2) by (x^2 - x - 12) will give you (5x+1) remainder 67x+10
(5x+1) is Q(x) and (67x+10) is Ax+B

Cheers :celebrate:

[Jtutor]

Herbie:

Hi jtutor, pls check yr pm

Hi Herbie,

As requested, I have just sent the Past Years' O Level Maths Trend Analysis to your email address.

Hope you find them useful.

Cheers!
Jtutor

[jovially]

Jtutor:

Herbie:

Hi jtutor, pls check yr pm

Hi Herbie,

As requested, I have just sent the Past Years' O Level Maths Trend Analysis to your email address.

Hope you find them useful.

Cheers!
Jtutor

Hi Jtutor,

May I have a copy too? TIA.

Cheers

[Skyed]

Amath is much easier to get A1 than emath. Not only cos the emath a1 is higher (90+) as compared to Amath, but Amath you keep drilling easy A1. You do enough questions already soon you realize they always test the same thing, and same way to solve.

[Jtutor]

jovially:

Jtutor:

[quote=\"Herbie\"]Hi jtutor, pls check yr pm

Hi Herbie,

As requested, I have just sent the Past Years' O Level Maths Trend Analysis to your email address.

Hope you find them useful.

Cheers!
Jtutor

Hi Jtutor,

May I have a copy too? TIA.

Cheers[/quote]Hi jovially,
I'm currently overseas and will forward you a copy once I'm back. Pls pm me your email address.
Cheers,
Jtutor

[Jtutor]

Hi jovially,


I’m back and have just forwarded you the compilation for your reference.
Hope you will find it useful for your child.

Cheers!
Jtutor