Math Problem Statement

Solve the system of equations: 1) -10x^2 + y = -80x + 155 2) 5x^2 + y = 40x - 85

Solution

The system of equations from the image is:

  1. 10x2+y=80x+155-10x^2 + y = -80x + 155
  2. 5x2+y=40x855x^2 + y = 40x - 85

Let's solve this system of equations step by step. To eliminate yy, we can subtract the second equation from the first.

  1. Subtract the second equation from the first: (10x2+y)(5x2+y)=(80x+155)(40x85)(-10x^2 + y) - (5x^2 + y) = (-80x + 155) - (40x - 85)

Simplifying both sides:

10x25x2+yy=80x40x+155+85-10x^2 - 5x^2 + y - y = -80x - 40x + 155 + 85 15x2=120x+240-15x^2 = -120x + 240

Now, divide the entire equation by 15-15:

x2=8x16x^2 = 8x - 16

Rearrange this into a standard quadratic form:

x28x+16=0x^2 - 8x + 16 = 0

This is a perfect square trinomial:

(x4)2=0(x - 4)^2 = 0

Thus, x=4x = 4.

  1. Substitute x=4x = 4 into either of the original equations to find yy. Let's use the second equation: 5(4)2+y=40(4)855(4)^2 + y = 40(4) - 85 5(16)+y=160855(16) + y = 160 - 85 80+y=7580 + y = 75 y=7580=5y = 75 - 80 = -5

So, the solution to the system is x=4x = 4 and y=5y = -5.

Would you like more details on this process or have any questions?

Here are 5 related questions to expand your understanding:

  1. How do you solve a system of equations using substitution?
  2. What is the difference between elimination and substitution methods in solving systems of equations?
  3. How would the solution change if one of the quadratic terms had a higher degree?
  4. Can a system of equations involving quadratics have multiple solutions? Why or why not?
  5. What are some real-world problems where solving systems of equations with quadratics is necessary?

Tip: Always double-check your solution by substituting the values back into both original equations to verify correctness.

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Equations
Systems of Equations

Formulas

Standard quadratic form ax^2 + bx + c = 0
Elimination method for systems of equations

Theorems

Basic quadratic equation solution methods

Suitable Grade Level

Grades 9-11