Question

how do you factor y^2 - 81

Answer 1

It is the difference of two squares.

Answer 2

Hint: You can write 81 as \(9^2\)

So, \(y^2 - 9^2 \)

Answer 3

Now use, \(\color{blue}{a^2 - b^2 = (a+b)(a-b)}\) identity.

Answer 4

Can you do it now @MathProblems22 ?

Answer 5

So basically you square root the number and then write it using (a +b)(a - b)

Answer 6

Not exactly , we determine the square root of the number and write it as : (sq. root of the number)^2

Answer 7

So that it becomes in the form of \(a^2 - b^2\)