Example 12 Factorise the following (i) 21x2y3 27x3y2 (ii) a3 – 4a2 12 – 3a (iii) 4x2 – x 25 (iv) 2 –9 9 y (v) x4 – 256 Solution (i) 21x2y3 27x3y2 = 3 × 7 × x × x × y × y × y 3 × 3 × 3 × x × x × x × y × y = 3 × x × x × y × y (7y 9x) (Using ab ac = a (b c)) = 3x2y2 (7y 9x) (ii) a3 – 4a2 12 – 3a = a2 (a – 4) – 3a 12 = a2 (a – 4Algebraic Identity means that the lefthand side of the equation is identical to the righthand side of the equation, and for all values of the variables Algebra Formulas for Class 9 (x9 y 3)/(x7 y 8) so that the answer has no negative exponents Expand the logarithm log x 2 y 3 zD) x=8 and y=0 Answer b Clarification If two complex numbers are equal, then corresponding parts are equal ie real parts of both are equal and imaginary parts of both are equal
Important Questions For Cbse Class 9 Maths Chapter 2 Polynomials
