Question

25x square -90xy +81ysquare

factorise !! ​

Answer 1

$25x {}^{2} - 90xy + 81y {}^{2}$

=>Write the number in the exponential form with an exponent of 2

$5 {}^{2} x {}^{2} - 90xy + 81y {}^{2}$

=>Write the expression as a product with the factors 5y and 9y

$5^{2} x {}^{2} - 2 \times 5x \times 9y + 81y {}^{2}$

=>Write the number in the exponential form with an exponent of 2

$5 {}^{2} x {}^{2} - 2 \times 5x \times 9y + 9 {}^{2} y {}^{2}$

=>Multiply the terms with equal exponents by multiplying their bases

$(5x) {}^{2} - 2 \times 5x \times 9y + (9y) {}^{2}$

=> Use $a {}^{2} - 2ab + b {}^{2} = (a - b) {}^{2}$ To factor the expression

• So here A=5x and B=9y

$(5x - 9y) {}^{2}$