Use Substitution to solve 10x - 15y = -70 and 3x - 5y = 15
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Use the substitution method to solve:
10x - 15y = - 70
3x - 5y = 15
Check Format
Equation 1 is in the correct format.
Check Format
Equation 2 is in the correct format.
Rearrange Equation 2 to solve for x:
3x - 5y = 15
Add 5y to both sides to isolate x
3x - 5y + 5y = 15 + 5y
3x = 15 + 5y
Now divide both sides by 3:
3x
3
=
15 + 5y
3
Revised Equation 2:
x =
15 + 5y
3
Plug Revised Equation 2 value into x:
10(x) - 15y = -70
10 * ((15 + 5y)/3) - 15y = -70
((150 + 50y)/3) - 15y = -70
Multiply equation 1 through by 3
3 * (((150 + 50y)/3) - 15y = -70)
3 * (((150 + 50y)/3) - 15y = -70)
150 + 50y - 45y = -210
Group like terms:
50y - 45y = -210 - 150
5y = -360
Divide each side by 5
5y
5
=
-360
5
y =
-360
5
y = -72
Plug this answer into Equation 1
10x - 15(-72) = -70
10x + 1080 = -70
10x = -70 - 1080
10x = -1150
Divide each side by 10
10x
10
=
-1150
10
x =
-1150
10
x = -115
What is the Answer?
x = -115 and y = -72
How does the Simultaneous Equations Calculator work?
Free Simultaneous Equations Calculator - Solves a system of simultaneous equations with 2 unknowns using the following 3 methods: 1) Substitution Method (Direct Substitution) 2) Elimination Method 3) Cramers Method or Cramers Rule
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2 equations 2 unknowns This calculator has 2 inputs.
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