Ninth Grade Math

 In the previous post we have discussed about Circle Area and In today's session we are going to discuss about Ninth Grade Math.


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In Ninth Grade Math, we study polynomials, in which we will learn about the types of polynomials, their degrees and thus we can calculate the zeros of polynomials. This chapter also includes the study of Remainder theorem and Factor theorem.

When we write the polynomial of 1 degree, we write it as ax + b. In case of a quadratic polynomial, we get two values of zeros and similarly a cubic polynomial has three zeros Further we say that to find the zeros of the given polynomial, we will equate the given polynomial to zero and thus we get the value of the variable.

Let us look at the following example : If p(x) = 3x - 6, then to find the value of zero of the polynomial, we proceed as follows:

3x – 6 = 0,

Or 3x = 6,

Or x = 6 / 3 = 2,

Thus we say that on putting the value of x = 2, we will get the value of the polynomial as zero. Let us check the above statement:

3 * (2) – 6 = 0,

6 – 6 = 0,

Now we will take the quadratic polynomial. Standard form of quadratic polynomial is ax² + bx + c, where we have a, b, c as rational numbers and 'a' is not equals to zero.

Now we say that if 25x² – 9 is the quadratic polynomial, then to find its zero, we say:

25x² – 9 = 0,

(5x)²  - 3² = 0,

Now applying the formula a² – b² = (a + b) * (a – b), we get:

 (5x + 3) * (5x – 3) = 0,

So either 5x + 3 = 0 or 5x – 3 = 0,

So, either x = -3/5 or x = 3/5,

Question based on Lateral Area of a Cone, is often found in the icse 2013 board papers.