## O-Level Elementary Math

### Re: O-Level Elementary Math

Please help with the following question

When f(x) is divided by x-1 and x+2 the remainders are 4 and -2 respectively. Hence find the remainder when f(x) is divided by X^2+X-2

When f(x) is divided by x-1 and x+2 the remainders are 4 and -2 respectively. Hence find the remainder when f(x) is divided by X^2+X-2

### Re: O-Level Elementary Math

Please help with the following question

When f(x) is divided by x-1 and x+2 the remainders are 4 and -2 respectively. Hence find the remainder when f(x) is divided by X^2+X-2

When f(x) is divided by x-1 and x+2 the remainders are 4 and -2 respectively. Hence find the remainder when f(x) is divided by X^2+X-2

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### Re: O-Level Elementary Math

This is classified as a challenging question on Factor Remainder Theorem for O-Level Additional Maths.0rchid123 wrote:Please help with the following question

When f(x) is divided by x-1 and x+2 the remainders are 4 and -2 respectively. Hence find the remainder when f(x) is divided by X^2+X-2

[Basics]

Given:

By remainder theorem

f(1) = 4

f(-2) = -2

Divisor

x^2 + x - 2 = (x + 2)(x - 1)

[Advance]

Do you know?

1) f(x) = Q(x) * Divisor + Remainder

2) The degree of the remainder is always less than that of the divisor. Example, a quadratic divisor (degree = 2) is given in this question, the remainder would have a degree of 1 or 0 so in general, we let remainder be Ax+B

f(x): Polynomial

Q(x): Quotient

f(x) = Q(x) *(x + 2)(x - 1) + (Ax + B)

When x = 1,

*Thinking process: How do we know what value of x to sub?*

f(1) = A + B

*Notice Q(x) 'disappears'*

4 = A + B --- (1)

When x = -2,

*Thinking process: How do we know what value of x to sub?*

f(-2) = -2A + B

*Notice Q(x) 'disappears'*

-2 = -2A + B --- (2)

Values of f(1) and f(-2) are obtained from the first few lines of the solution.

A = 2

B = 2

Hence remainder = 2x + 2 = 2(x + 1)

### Re: O-Level Elementary Math

Hi can somebody help me with this qtn, thank you!

The volume of a block is 0.03 cubic metres, correct to the nearest 0.01 cubic metres. Find the greatest possible height of the block in metres.

The volume of a block is 0.03 cubic metres, correct to the nearest 0.01 cubic metres. Find the greatest possible height of the block in metres.

### Re: O-Level Elementary Math

Anyone giving Sec 3 & 4 Maths textbook by Shinglee? or at least selling cheap? Thank you

- sundarshoba
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