Math Problem Statement

y=x+7 and yx=-12

Solution

You have two equations here:

  1. y=x+7y = x + 7
  2. yx=12yx = -12

We can solve this system of equations by substituting the expression for yy from the first equation into the second equation.

Step 1: Substitute y=x+7y = x + 7 into yx=12yx = -12

Since y=x+7y = x + 7, replace yy in the second equation:

(x+7)x=12(x + 7)x = -12

This simplifies to:

x2+7x+12=0x^2 + 7x + 12 = 0

Step 2: Solve the quadratic equation

Now we have a quadratic equation:

x2+7x+12=0x^2 + 7x + 12 = 0

To solve this, we can factor the equation. We need two numbers that multiply to 1212 and add up to 77. Those numbers are 33 and 44.

So, we can factor as:

(x+3)(x+4)=0(x + 3)(x + 4) = 0

Step 3: Find the values of xx

Set each factor equal to zero:

  1. x+3=0x=3x + 3 = 0 \Rightarrow x = -3
  2. x+4=0x=4x + 4 = 0 \Rightarrow x = -4

Step 4: Find the corresponding values of yy

Now, substitute these values of xx back into y=x+7y = x + 7 to find yy:

  • For x=3x = -3: y=3+7=4y = -3 + 7 = 4

  • For x=4x = -4: y=4+7=3y = -4 + 7 = 3

Solution

The solutions to the system are:

  1. (x,y)=(3,4)(x, y) = (-3, 4)
  2. (x,y)=(4,3)(x, y) = (-4, 3)

Would you like a deeper explanation on any part of this process?

Here are some related questions you may find helpful:

  1. How do you solve systems of equations by substitution?
  2. What are the steps to factor quadratic equations?
  3. How can we confirm the solutions to a system of nonlinear equations?
  4. What other methods exist to solve systems of equations?
  5. How do substitution and elimination methods compare in solving systems of equations?

Tip: Always check your solutions by substituting them back into the original equations to ensure accuracy.

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Math Problem Analysis

Mathematical Concepts

Algebra
Systems of Equations
Quadratic Equations

Formulas

y = x + 7
yx = -12
Factoring of quadratic equations

Theorems

Quadratic factoring
Substitution method

Suitable Grade Level

Grades 8-10