Table of contents  
PolynomialsDefinition of a Polynomial  
Remainder Theorem  
Factor Theorem  
General Theory of Equations  
Linear Equation  
Quadratic Equations 
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Let be real numbers and x is a real variable. Then f(x) = is called a real polynomial of real variable x with coefficients
Example: is a polynomial
The degree of a polynomial is the highest power of the variable in the polynomial.
Q.1. Find the degree of the polynomial 6x^{4}+ 3x^{2}+ 5x +19
Ans: The degree of the polynomial is 4.
Q.2. Find the degree of the polynomial 6x^{3}+4x^{3}+3x+1
Ans: The degree of the polynomial is 3.
If any polynomial f(x) is divided by (x  a) then f(a) is the remainder.
If (x  a) is a factor of f(x), then remainder f(a) = 0. (Or) if f(a) = 0, then (x  a) is a factor of f(x),
Q.1. Find the remainder by using the remainder theorem when polynomial x^{3}−3x^{2}+x+1 is divided by x−1.
Ans:
Q.2. Find the remainder when p(x)= −x+3x^{2}−1 is divided by x+1.
Ans:
A linear equation is 1^{st} degree equation. It has only one root. Its general form is a
Quadratic Equation in “x” is one in which the highest power of “x” is 2. The equation is generally satisfied by two values of “x”.

The quadratic equation ax^{2} + bx + c = 0 will have maximum or minimum value at x =  b/2a. If a < 0, it has maximum value and if a > 0, it has minimum value.
The maximum or minimum value is given by
Ex.2. A and B went to a hotel paid Rs. 84 for 3 plates of Idli and 5 plates of Dosa. Whereas B took 5 plates of Idli and 3 plates of Dosa and paid Rs. 76. What is the cost of one plate of Idli.
 3I + 5D = 84 ……….(1)
 5I + 3D = 76 ………(2)
 Equation (1) × 3  equation (2) × 5, we get
⇒ 16I = 128
⇒ I = 8 Each plate of Idli cost Rs. 8.
Ex.3. Find the values of x and y from the equations
Ex.4. Find x and y from
Ex.5. Aman won a competition and so he got some prize money. He gave Rs. 2000 less than the half of prize money to his son and Rs. 1000 more than the two third of the remaining to his daughter. If both they got same amount, what is the prize money Aman got?
Ex.6. How many non negative integer pairs (x, y) satisfy the equation, 3x + 4y = 21?
 Since x and y are non negative integers. Start from x = 0.
 If x = 0 or 2, y cannot be integer.
 For x = 3, y = 3.
And for x = 7, y = 0. These two pairs only satisfy the given equation.
Ex.7. If (x  2) is a factor of x^{3}  3x^{2} + px + 4. Find the value of p.
 Since (x  2) is a factor, f(2) = 0.
 ∴ 2^{3}  3(2^{2}) + (2)p + 4 = 0
⇒ p = 0
Ex.8. When x^{3}  7x^{2} + 3x  P is divided by x + 3, the remainder is 4, then what is the value of P ?
 f( 3) = 4
 ∴ ( 3)^{3}  7( 3)^{2} + 3( 3)  P = 4
 P =  103.
Ex.9. If (x  1) is the HCF of (x^{3}  px^{2} + qx  3) and (x^{3}  2x^{2} + px + 2). What is the value of ‘q’?
 Since (x  1) is HCF, it is a factor for both the polynomials.
 ∴ 1^{3}  p(1)^{2} + q(1)  3 = 0
  p + q = 2
 And 1^{3}  2(1^{2}) + p(1) + 2 = 0
 p =  1
 ∴ q = 1
Ex.10. Find the roots of the quadratic equation x^{2}  x  12 = 0.
 x^{2}  x  12 = 0
 x^{2}  4x + 3x  12 = 0
 x(x  4) + 3(x  4) = 0
 (x  4) (x + 3) = 0
 x = 4 or 3
 The roots are 4 and 3.
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163 videos163 docs131 tests
