if x^2-y^2=21 and x-y=7 then what would be x+y
Answers
Answered by
0
Answer:
x
2
−
y
2
=
21
,
x
+
y
=
7
Subtract
y
from both sides of the equation.
x
=
7
−
y
x
2
−
y
2
=
21
Replace all occurrences of
x
in
x
2
−
y
2
=
21
with
7
−
y
.
x
=
7
−
y
(
7
−
y
)
2
−
y
2
=
21
Simplify
(
7
−
y
)
2
−
y
2
.
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x
=
7
−
y
49
−
14
y
=
21
Solve for
y
in the second equation.
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x
=
7
−
y
y
=
2
Replace all occurrences of
y
in
x
=
7
−
y
with
2
.
x
=
7
−
(
2
)
y
=
2
Simplify
7
−
(
2
)
.
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x
=
5
y
=
2
The solution to the system of equations can be represented as a point.
(
5
,
2
)
Step-by-step explanation:
Answered by
0
Answer:
x²-y²=(x-y)(x+y)
x+y=(x²-y²)/(x-y)
=21/7
=3 Answer
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