Solve the system and give the solution.
2x + 8y = 6
5x + 20y = 15
Answers
Answer:
15
Step-by-step explanation:
This system of equation doesn't have any solutions.
Explanation:
2
x
+
8
y
=
6
−
5
x
−
20
y
=
−
15
Let's simplify these equations: divide the first one by
2
andd the second by
−
5
:
x
+
4
y
=
3
x
+
4
y
=
15
Now, using any of the equations, we must express one variable by the other, let's say
x
by
y
from the second equation:
x
=
15
−
4
y
Using this we solve the other equation:
x
+
4
y
=
3
15
−
4
y
+
4
y
=
3
15
=
3
We got
15
=
3
which obviously isn't true so this equation has no solution. It follows that this system of equation doesn't have any solutions as well.
Answer link
EZ as pi
Nov 19, 2016
x
can have any value and the equations will work.
The y- values will depend on the x chosen.
Explanation:
2
x
+
8
y
=
6
and
−
5
x
−
20
y
=
−
15
There are different options available to solve the equations.
→
elimination
→
substitution
→
single variable
→
equating
→
matrices
→
graphically
To be able to use substitution, a single variable in one of the equations is a useful indicator
2
x
+
8
y
=
6
÷
2
→
x
+
4
y
=
3
Make x the subject of the equation:
x
=
3
−
4
y
Replace
x
in the second equation by
(
3
−
4
y
)
−
5
x
−
20
y
=
−
15
×
×
↓
−
5
(
3
−
4
y
)
−
20
y
=
−
15
−
15
+
20
y
−
20
y
=
−
15
−
15
=
−
15
x
can have any value
Answer link
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