# SAT Math Multiple Choice Question 799: Answer and Explanation

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**Question: 799**

**4.** How many solutions does the system of equations shown above have?

- A. 0
- B. 1
- C. 2
- D. Infinitely many

**Correct Answer:** D

**Explanation:**

**D**

**Difficulty:** Easy

**Category:** Heart of Algebra / Systems of Linear Equations

**Strategic Advice:** When a question about a system of equations asks for the *number* of solutions, rather than the actual solution, don't worry about finding the value of *x* and *y* right away-you might not even need them to answer the question. Just simplify the two equations as much as possible, and then compare them.

**Getting to the Answer:** For each equation, combine like terms and write the results in standard form (*Ax* + *By* = *C*):

The equations are identical (dependent) and therefore represent the same line, which means the system has infinitely many solutions, making (D) correct.