Question

If a number is subtracted from its square the remainder is 20 then find the number

Answer 1

Answer:

(a^2)/20

Step-by-step explanation:

let x be the number

a^2- x = 20

x= (a^2)/20

Answer 2

Given

• If a number is subtracted from its square the remainder is 20

Explanation:

Let the number be x

again, Its square be x²

$\maltese {\underline{\pmb{\sf{ According \ to \ Question: }}}} \\ \\ \\ \colon\implies{\sf{ x^2-x = 20 }} \\ \\ \\ \colon\implies{\sf{ x^2-x-20 = 0 }} \\ \\ \\ \colon\implies{\sf{ x^2-(5-4)x-20 = 0 }} \\ \\ \\ \colon\implies{\sf{ x^2-5x+4x-20 = 0 }} \\ \\ \\ \colon\implies{\sf{ x(x-5)+4(x-5) = 0 }} \\ \\ \\ \colon\implies{\sf{ (x-5)(x+4) = 0 }} \\ \\ \\ \colon\implies{\sf{ x = 5 \ or \ -4 }}$

Here, The number can't be Negative ( –ve ).

Hence,

• The Number will be 5 .

More to Know

• a² - b² = (a + b) (a - b)
• a² + b² = (a + b)² - 2ab
• a³ + b³ = (a + b) (a²+b²-ab)
• a³ - b³ = (a - b) (a² + b² + ab)
• a⁴ + b⁴ = {(a + b)² - 2ab}² - 2(ab)²