find the value of x &y; x+y= 7 2x-4y= -10
Answers
Step-by-step explanation:
Course menu
Socratic Q&A logo
Search icon
Simultaneous equations
2
x
+
4
y
=
1
and
3
x
−
5
y
=
7
. What do
x
and
y
equal?
Algebra
1 Answer
smendyka
Jul 25, 2018
See a solution process below:
Explanation:
Step 1) Solve the first equation for
x
:
2
x
+
4
y
=
1
2
x
+
4
y
−
4
y
=
1
−
4
y
2
x
+
0
=
1
−
4
y
2
x
=
1
−
4
y
2
x
2
=
1
−
4
y
2
x
=
1
2
−
4
y
2
x
=
1
2
−
2
y
Step 2) Substitute
(
1
2
−
2
y
)
for
x
in the second equation and solve for
y
:
3
x
−
5
y
=
7
becomes:
3
(
1
2
−
2
y
)
−
5
y
=
7
(
3
×
1
2
)
−
(
3
×
2
y
)
−
5
y
=
7
3
2
−
6
y
−
5
y
=
7
3
2
−
11
y
=
7
3
2
−
3
2
−
11
y
=
7
−
3
2
0
−
11
y
=
(
2
2
×
7
)
−
3
2
−
11
y
=
14
2
−
3
2
−
11
y
=
14
−
3
2
−
11
y
=
11
2
−
11
y
×
−
1
11
=
11
2
×
−
1
11
−
11
−
11
y
=
11
2
×
−
1
11
y
=
−
1
2
Step 3) Substitute
−
1
2
for
y
in the solution to the first equation at the end of Step 1 and calculate
x
:
x
=
1
2
−
2
y
becomes:
x
=
1
2
−
(
2
×
−
1
2
)
x
=
1
2
−
(
−
2
2
)
x
=
1
2
+
2
2
x
=
1
+
2
2
x
=
3
2
The Solution Is:
x
=
3
2
and
y
=
−
1
2
Or
(
3
2
,
−
1
2
)
Answer:
x=3
y=4
Step-by-step explanation:
x+y=7
=>x=7-y
if we put the value of x in the 2nd equation
2x-4y= -10
=>2(7-y) - 4y = -10
=>14-2y-4y = -10
=>14-6y = -10
=>6y= 14+10= 24
=>y=24/6=4
we got the value of y=4, If we put it on equation1
then,
x+y=7
=>x+4=7
=>x=7-4=3
Therefore
x=3, y=4