Use Substitution to solve 3d 8i = 64 and 9d 7i = 107
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Use the substitution method to solve:
3d + 8i = 64
9d + 7i = 107
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:
9d + 7i = 107
Subtract 7i from both sides to isolate d:
9d + 7i - 7i = 107 - 7i
9d = 107 - 7i
Now divide by 9:
9d
9
=
107 - 7i
9
Revised Equation 2:
d =
107 - 7i
9
Plug Revised Equation 2 value into d:
3(d) + 8i = 64
3 * ((107 - 7i)/9) + 8i = 64
((321 - 21i)/9) + 8i = 64
Multiply equation 1 through by 9
9 * (((321 - 21i)/9) + 8i = 64)
9 * (((321 - 21i)/9) + 8i = 64)
321 - 21i + 72i = 576
Group like terms:
-21i + 72i = 576 - 321
51i = 255
Divide each side by 51
51i
51
=
255
51
i =
255
51
i = 5
Plug this answer into Equation 1
3d + 8(5) = 64
3d + 40 = 64
3d = 64 - 40
3d = 24
Divide each side by 3
3d
3
=
24
3
d =
24
3
d = 8
What is the Answer?
d = 8 and i = 5
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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