factorise:
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0
Answer:
x⁴-81
(x²)²-(9)²
(x²+9)(x²-9)
(x²+9)(x+3)(x-3)
Answered by
0
Step-by-step explanation:
x
4
−
81
Rewrite
x
4
as
(
x
2
)
2
.
(
x
2
)
2
−
81
Rewrite
81
as
9
2
.
(
x
2
)
2
−
9
2
Since both terms are perfect squares, factor using the difference of squares formula,
a
2
−
b
2
=
(
a
+
b
)
(
a
−
b
)
where
a
=
x
2
and
b
=
9
.
(
x
2
+
9
)
(
x
2
−
9
)
Simplify.
(x2+9) (x+3) (x−3)
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