Math Problem Statement

Solve the following simultaneous equations: y = x^2 and 7x + 2y = 4. Give your answers as integers or decimals.

Solution

Let's solve the system of equations:

  1. y=x2y = x^2
  2. 7x+2y=47x + 2y = 4

Step 1: Substitute yy from the first equation into the second equation.

From equation (1), we know that y=x2y = x^2. Now substitute this into equation (2):

7x+2(x2)=47x + 2(x^2) = 4

Step 2: Simplify and solve the resulting quadratic equation.

7x+2x2=47x + 2x^2 = 4

Rearrange the terms to form a standard quadratic equation:

2x2+7x4=02x^2 + 7x - 4 = 0

Step 3: Solve the quadratic equation using the quadratic formula.

The quadratic formula is given by:

x=b±b24ac2ax = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}

For the equation 2x2+7x4=02x^2 + 7x - 4 = 0, the coefficients are a=2a = 2, b=7b = 7, and c=4c = -4. Substituting these into the quadratic formula:

x=7±724(2)(4)2(2)x = \frac{-7 \pm \sqrt{7^2 - 4(2)(-4)}}{2(2)} x=7±49+324x = \frac{-7 \pm \sqrt{49 + 32}}{4} x=7±814x = \frac{-7 \pm \sqrt{81}}{4} x=7±94x = \frac{-7 \pm 9}{4}

Thus, we have two possible solutions for xx:

  1. x=7+94=24=0.5x = \frac{-7 + 9}{4} = \frac{2}{4} = 0.5
  2. x=794=164=4x = \frac{-7 - 9}{4} = \frac{-16}{4} = -4

Step 4: Find corresponding yy-values.

Using the first equation y=x2y = x^2, we can now find the corresponding yy-values for each xx-solution:

  • For x=0.5x = 0.5, y=(0.5)2=0.25y = (0.5)^2 = 0.25
  • For x=4x = -4, y=(4)2=16y = (-4)^2 = 16

Final Solutions:

The solutions to the system of equations are:

  • x=0.5,y=0.25x = 0.5, y = 0.25
  • x=4,y=16x = -4, y = 16

Do you need further details on the solution or have additional questions?

Related Questions:

  1. How do you use the quadratic formula to solve quadratic equations?
  2. What are the real-world applications of quadratic equations?
  3. Can you solve a system of equations involving linear and quadratic functions graphically?
  4. How do you check the solutions of a system of equations?
  5. How do you approach a system with more than two equations?

Tip:

When solving a system of equations involving a quadratic and linear equation, substitution is a great method to simplify the problem.

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Equations
Simultaneous Equations

Formulas

Quadratic formula: x = (-b ± √(b² - 4ac)) / 2a
Substitution method for solving equations

Theorems

Quadratic formula theorem

Suitable Grade Level

Grades 9-11