- A2
- B1/3
- C3
- D1/2
Step-by-Step Solution
The pair becomes and . Multiply by 4 and 3: and . Add: → , then . Now UNDO the substitution: (and ). Answering 2 means stopping at and forgetting that is , not ; 1/3 is .
Answer: D) 1/2
Solve and by putting and . Find .
Class 10Pair of Linear Equations in Two VariablesAlgebra — Systems of Equations
Key idea: Substitution method
**Steps**:
1. From one equation, express ONE variable in terms of the other.
2. Substitute into the OTHER equation. You get a one-variable equation.
3. Solve.
4. Plug back to find the other variable.
**Example**: ... (i); ... (ii).
- From (ii): .
- Substitute in (i): → → .
- Then .
- Solution: .
1. From one equation, express ONE variable in terms of the other.
2. Substitute into the OTHER equation. You get a one-variable equation.
3. Solve.
4. Plug back to find the other variable.
**Example**: ... (i); ... (ii).
- From (ii): .
- Substitute in (i): → → .
- Then .
- Solution: .
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