Question

What is

Factorise:
4x squared -1
9x squared -64
49x squared -121
4x squared -y squared
9a squared -b squared
16a squared -9b squared
x squared -42 squared

Please help me ASAP

Answer 1

i am just here to troll lol

Answer 2

Step-by-step explanation:

There is a theorem :

`\mathbf{a^(2)-b^(2)=(a-b)(a+b)}`

Proof: open the brackets on right side of equality by using distributive property

RHS = a(a+b) - b(a+b)

RHS =
`\mathrm{a^(2)+ab-ab-b^(2)}`

RHS =
`\mathrm{a^(2)-b^(2)}` = LHS

Using the above theorem you can solve every question you asked:

• 
  `\mathrm{4x^(2)-1=(2x)^(2)-1^(2)=(2x-1)(2x+1)}`
• 
  `\mathrm{9x^(2)-64=(3x)^(2)-(8)^(2)=(3x-8)(3x+8)}`

• 
  `\mathrm{49x^(2)-121=(7x)^(2)-(11)^(2)=(7x-11)(7x+11)}`

• 
  `\mathrm{4x^(2)-y^(2)=(2x)^(2)-y^(2)=(2x-y)(2x+y)}`

• 
  `\mathrm{9x^(2)-b^(2)=(3x)^(2)-b^(2)=(3x-b)(3x+b)}`

• 
  `\mathrm{16x^(2)-9b^(2)=(4x)^(2)-(3b)^(2)=(4x-3b)(4x+3b)}`

• 
  `\mathrm{x^(2)-42^(2)=(x-42)(x+42)}`