2x + 5y = 20; 3x + 6y = 12.
Answers
Answer:
hey mate
Explanation:
Let's isolate
x
in the first:
x
=
18
3
−
6
y
3
x
=
6
−
2
y
Now, we replace this found
x
in the second:
2
(
6
−
2
y
)
+
5
y
=
20
12
−
4
y
+
5
y
=
20
12
+
y
=
20
y
=
8
Now, you just replace this
y
=
8
in the isolated
x
above:
x
=
6
−
2
(
8
)
x
=
6
−
16
=
−
10
Answer:
2x+5y=20,3x+6y=12
To solve a pair of equations using substitution, first solve one of the equations for one of the variables. Then substitute the result for that variable in the other equation.
2x+5y=20,3x+6y=12
2x+5y=20,3x+6y=12
xx
2x+5y=20
2x+5y=20
5y
2x=-5y+20
2x=−5y+20
2
x=\frac{1}{2}\left(-5y+20\right)
x=
2
1
(−5y+20)
\frac{1}{2}=0.5
-5y+20
x=-\frac{5}{2}y+10
x=−
2
5
y+10
-\frac{5y}{2}+10
x3x+6y=12
3\left(-\frac{5}{2}y+10\right)+6y=12
3(−
2
5
y+10)+6y=12
3-\frac{5y}{2}+10
-\frac{15}{2}y+30+6y=12
−
2
15
y+30+6y=12
-\frac{15y}{2}
6y
-\frac{3}{2}y+30=12
−
2
3
y+30=12
30
-\frac{3}{2}y=-18
−
2
3
y=−18
-\frac{3}{2}=-1.5
y=12
y=12
12yx=-\frac{5}{2}y+10
x
x=-\frac{5}{2}\times 12+10
x=−
2
5
12+10
-\frac{5}{2}=-2.5
12
x=-30+10
x=−30+10
10-30
x=-20
x=−20
Explanation
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