Math Problem Statement

Solve the system by elimination. Select the solution(s). 2x^2 - 3x - y = -5, -x + y = 5

Solution

To solve the system of equations by elimination, we have the following two equations:

  1. 2x23xy=52x^2 - 3x - y = -5
  2. x+y=5-x + y = 5

Step 1: Solve the second equation for yy

From the second equation, x+y=5-x + y = 5, we can isolate yy: y=x+5y = x + 5

Step 2: Substitute y=x+5y = x + 5 into the first equation

Substitute this expression for yy into the first equation 2x23xy=52x^2 - 3x - y = -5: 2x23x(x+5)=52x^2 - 3x - (x + 5) = -5

Simplify the equation: 2x23xx5=52x^2 - 3x - x - 5 = -5 2x24x5=52x^2 - 4x - 5 = -5

Step 3: Solve for xx

Now, add 5 to both sides: 2x24x=02x^2 - 4x = 0

Factor out 2x2x: 2x(x2)=02x(x - 2) = 0

Thus, x=0x = 0 or x=2x = 2.

Step 4: Solve for yy

  • If x=0x = 0, substitute into y=x+5y = x + 5: y=0+5=5y = 0 + 5 = 5 So, one solution is (0,5)(0, 5).

  • If x=2x = 2, substitute into y=x+5y = x + 5: y=2+5=7y = 2 + 5 = 7 So, another solution is (2,7)(2, 7).

Step 5: Check solutions in the original system

  • For (0,5)(0, 5):

    • First equation: 2(0)23(0)5=52(0)^2 - 3(0) - 5 = -5, which is true.
    • Second equation: 0+5=5-0 + 5 = 5, which is true.
  • For (2,7)(2, 7):

    • First equation: 2(2)23(2)7=52(2)^2 - 3(2) - 7 = -5, which simplifies to 867=58 - 6 - 7 = -5, true.
    • Second equation: 2+7=5-2 + 7 = 5, which is true.

Both solutions are valid. Therefore, the correct answers are:

  • (0,5)(0, 5)
  • (2,7)(2, 7)

Do you want more details or have any questions?

Related Questions:

  1. How does substitution differ from elimination in solving systems of equations?
  2. Can this system of equations be solved graphically, and how would the graphs look?
  3. What are the advantages of using elimination over substitution?
  4. How would this system change if the second equation was altered slightly, like x+y=6-x + y = 6?
  5. What methods are used to solve systems of nonlinear equations?

Tip: Always check your solutions in both equations to verify accuracy, especially in systems with quadratic components!

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Math Problem Analysis

Mathematical Concepts

Algebra
Systems of Equations
Quadratic Equations

Formulas

Quadratic equation ax^2 + bx + c = 0
Substitution method y = x + 5

Theorems

Quadratic formula
Zero Product Property

Suitable Grade Level

Grades 9-11