Question:3`y^2` + 81
Answer
3`y^2` + 81 =3(`y^2`+27)
Question:3`y^2` + 81
3`y^2` + 81 =3(`y^2`+27)
Question:Factorise `a^2` +2ab +`b^2`
`a^2` +2ab +`b^2` =`a^2` + ab +ab +`b^2` =a(a+b) +b(a+b) =(a+b) (a+b) =`(a+b)^2`
Question:What number must be added to (`x^2` +6x) to make the result a perfect square?
(`x^2` + 6x) =`x^2` + `2.x.3` + `3^2` - 9 =`(x+3)^2` - 9 [here `(x+3)^2` is perfect square ] `:.` to make (`x^2` +6x) perfect , 9 must be added
Question:what number must be added to (`x^2` -18x) to make the result a perfect square?
(`x^2` -18x) =`x^2` - 2 . x .9 +`9^2` - 81 =`(x-9)^2` - 81 [ here `(x-9)^2` is perfect squire ] `:.` to make (`x^2` - 18x) perfect , 81 must be added
Question:Factorise ax + 3a - xy -3y
ax + 3a - xy -3y =a(x+3) - y(x+3) =(x+3) (a-y)