IXL - Complete the square (Algebra 2 practice)

or

Complete the square. Fill in the number that makes the polynomial a perfect-square quadratic.

m² + 6m +

ref_doc_title.

or

Learn with an example

question

Complete the square. Fill in the number that makes the polynomial a perfect-square quadratic.

u² + 4u +

key idea

With
quadratic
expressions
like
x ²
+
b x ,
you
can
complete
the
square
by
adding
b
2
²
.

solution

Add
b
2
²
to
complete
the
square.

u

²

+

4

u

+

b

2

²

Plug in b = 4

=

u

²

+

4

u

+

4

2

²

Plug in b = 4

Divide

=

u² + 4u + 2²

Divide

Square

=

u² + 4u + 4

Square

This
quadratic
can
be
written
as
a
square,
(u + 2)²
,
so
it
is
a
perfect-square
quadratic.
The
number
needed
to
complete
the
square
was
4
.

Looking for more? Try these:

Lesson: Completing the square

or

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X.7Factor quadratics: special cases

Lesson: Completing the square