Question

Y*2-81=0 find roots tf equation

Answer 1

${y}^{2} - 81$
can be written in the form of
${a}^{2} - {b}^{2} = (a+b)(a-b)$
then find roots of y
answer will be
the equation has two roots y=9 and y= -9

Answer 2

Let p(y) =y^2-81
=(y)^2-(9)^2
=(y+9)(y-9)
Therefore, the two roots of p(y) are:
y+9=0
=>y=-9
y-9=0
=>y=9