Use Substitution to solve f t = 15 and 5f 20t = 180
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Use the substitution method to solve:
f + t = 15
5f + 20t = 180
Check Format
Equation 1 is in the correct format.
Check Format
Equation 2 is in the correct format.
Rearrange Equation 2 to solve for f:
5f + 20t = 180
Subtract 20t from both sides to isolate f:
5f + 20t - 20t = 180 - 20t
5f = 180 - 20t
Now divide by 5:
5f
5
=
180 - 20t
5
Revised Equation 2:
f =
180 - 20t
5
Plug Revised Equation 2 value into f:
1(f) + t = 15
1 * ((180 - 20t)/5) + t = 15
((180 - 20t)/5) + t = 15
Multiply equation 1 through by 5
5 * (((180 - 20t)/5) + t = 15)
5 * (((180 - 20t)/5) + t = 15)
180 - 20t + 5t = 75
Group like terms:
-20t + 5t = 75 - 180
-15t = -105
Divide each side by -15
-15t
-15
=
-105
-15
t =
-105
-15
t = 7
Plug this answer into Equation 1
1f + 1(7) = 15
1f + 7 = 15
1f = 15 - 7
1f = 8
Divide each side by 1
1f
1
=
8
1
f =
8
1
f = 8
algo = 0 title = Use Substitution to solve f + t = 15 and 5f + 20t = 180 pl = 1
What is the Answer?
f = 8 and t = 7
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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