You’ve uploaded an image showing a
step-by-step solution to a system of linear equations using the
elimination method, followed by substitution and verification. Let’s walk through the problem, explain each step clearly, and confirm the solution is correct.
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## 🧩 The System of Equations
We are given:
>
Equation 1: `3x + 3y = 11.25`
>
Equation 2: `4x + 2y = 10`
We want to find values of `x` and `y` that satisfy
both equations simultaneously.
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##
✔ Step 1: Eliminate One Variable (Elimination Method)
The goal is to
add or subtract the equations to eliminate one variable. To do this, we make the coefficients of one variable
opposites (e.g., +6y and -6y).
Multiply Equation 1 by 2:
> `2 × (3x + 3y) = 2 × 11.25`
> → `6x + 6y = 22.50`
Multiply Equation 2 by -3:
> `-3 × (4x + 2y) = -3 × 10`
> → `-12x - 6y = -30`
Now write them together:
```
6x + 6y = 22.50
-12x - 6y = -30
------------------
```
Add them vertically:
- `6x + (-12x) = -6x`
- `6y + (-6y) = 0`
- `22.50 + (-30) = -7.50`
So we get:
>
-6x = -7.50
Divide both sides by -6:
>
x = (-7.50) / (-6) = 1.25
✔ So,
x = 1.25
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##
✔ Step 2: Substitute x Back to Find y
Now plug `x = 1.25` into
one of the original equations. The image uses Equation 2: `4x + 2y = 10`
Substitute:
> `4(1.25) + 2y = 10`
> → `5 + 2y = 10`
Subtract 5 from both sides:
> `2y = 5`
Divide by 2:
>
y = 2.5
✔ So,
y = 2.5
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##
✔ Step 3: Check the Solution in Both Equations
We now verify that `(x, y) = (1.25, 2.5)` satisfies
both original equations.
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🔍 Check in Equation 1: `3x + 3y = 11.25`
> `3(1.25) + 3(2.5) = ?`
> → `3.75 + 7.5 = 11.25` ✔️
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🔍 Check in Equation 2: `4x + 2y = 10`
> `4(1.25) + 2(2.5) = ?`
> → `5 + 5 = 10` ✔️
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## 🎯 Final Answer:
>
The solution to the system is `(x, y) = (1.25, 2.5)`
This means the two lines represented by the equations intersect at the point `(1.25, 2.5)`.
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## 💡 Key Takeaways:
-
Elimination Method: Multiply equations to create opposite coefficients, then add to eliminate a variable.
-
Substitution: Once you have one variable, plug it back into any equation to solve for the other.
-
Verification: Always check your solution in
both original equations to ensure accuracy.
---
✔ Your work in the image is
perfectly correct — great job following the steps! The solution `(1.25, 2.5)` is accurate and verified.
Let me know if you’d like to see how to solve this using graphing or substitution from the start!
Parent Tip: Review the logic above to help your child master the concept of 3 variable system of equations word problems worksheet.