Use Substitution to solve 0.1d + 0.25q = 2.25 and d + q = 12

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Use the substitution method to solve:

0.1d + 0.25q = 2.25

d + q = 12

Check Format

Equation 1 is in the correct format.

Check Format

Equation 2 is in the correct format.

Rearrange Equation 2 to solve for d:

d + q = 12

Subtract q from both sides to isolate d:

d + q - q = 12 - q

d = 12 - q

Plug Revised Equation 2 value into d:

0.1(d) + 0.25q = 2.25

0.1 * (12 - q) + 0.25q = 2.25

1.2 - 0.1q + 0.25q = 2.25

Group like terms:

-0.1q + 0.25q = 2.25 - 1.2

0.15q = 1.05

Divide each side by 0.15

0.15q

0.15

=

1.05

0.15

q =

1.05

0.15

q = 7

Plug this answer into Equation 1

0.1d + 0.25(7) = 2.25

0.1d + 1.75 = 2.25

0.1d = 2.25 - 1.75

0.1d = 0.5

Divide each side by 0.1

0.1d

0.1

=

0.5

0.1

d =

0.5

0.1

d = 5

What is the Answer?

d = 5 and q = 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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2 equations 2 unknowns This calculator has 2 inputs.

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