7.Solve and check the equations:
(a) 5x - 7 = 2x + 8
(b) 15( y- 4) - 2( y -9) + 5 (y + 6 ) = 0
Answers
Answer:
5x-7=2x+8
taking everything on one side....
5x-7-2x-8=0
3x-15=0
3x=15
x=5
Answer:
Step-by-step explanation:
Equation 1
:
5
x
+
y
=
6
Equation 2
:
12
x
−
2
y
=
−
16
We can solve the system by elimination.
Multiply Equation 1 by
2
.
2
(
5
x
+
y
=
6
)
10
x
+
2
y
=
12
Add Equation 1 and Equation 2.
10
x
+
2
y
=
...
.
12
12
x
−
2
y
=
−
16
−
−
−
−
−
−
−
22
x
...
...
.
.
=
−
4
Divide both sides by
22
.
x
=
−
4
22
Simplify.
x
=
−
2
11
or
≈
−
0.18
Substitute the value for
x
into Equation 1. Solve for
y
.
5
x
+
y
=
6
5
(
−
2
11
)
+
y
=
6
Expand.
−
10
11
+
y
=
6
Add
10
11
to both sides.
y
=
6
+
10
11
Multiply
6
by
11
11
to get an equivalent fraction with
11
as the denominator.
y
=
6
×
11
11
+
10
11
y
=
66
11
+
10
11
y
=
76
11
or
≈
6.9
The solution to the linear system is
(
−
2
11
,
76
11
)
.
The approximate solution is
(
−
0.18
,
6.9
)
.
graph{(5x+y-6)(12x-2y+16)=0 [-7.52, 6.53, 1.603, 8.627]}
Nallasivam V
May 12, 2018
Answer:
x
=
−
2
11
y
=
76
11
Explanation:
Given -
5
x
+
y
=
6
--------- (1)
12
x
−
2
y
=
−
16
------(2)
5
x
+
y
=
6
--------- (1)
×
2
12
x
−
2
y
=
−
16
------(2)
10
x
+
2
y
=
12
--------(3)
12
x
−
2
y
=
−
16
-------(2) --
(
3
)
+
(
2
)
22
x
=
−
4
x
=
−
4
22
=
−
2
11
x
=
−
2
11
Plug in
x
=
−
2
11
in equation (1)
5
(
−
2
11
)
+
y
=
6
−
10
11
+
y
=
6
y
=
6
+
10
11
=
66
+
10
11
=
76
11
y
=
76
11