x²+4x_9=0 find the root completing the square
Answers
Answered by
2
Answer:
13
Step-by-step explanation:
The difference of squares identity can be written:
a
2
−
b
2
=
(
a
−
b
)
(
a
+
b
)
Hence we find:
0
=
x
2
+
4
x
−
9
0
=
x
2
+
4
x
+
4
−
13
0
=
(
x
+
2
)
2
−
(
√
13
)
2
0
=
(
(
x
+
2
)
−
√
13
)
(
(
x
+
2
)
+
√
13
)
0
=
(
x
+
2
−
√
13
)
(
x
+
2
+
√
13
)
Hence:
x
=
−
2
±
√
13
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