how can i solve them? show work please

5 hours ago 1
Nature

To solve math problems effectively, here are some step-by-step strategies with examples:

  1. Draw a model or diagram: Visualizing the problem by drawing can help understand the relationships and make it easier to solve.
  2. Act it out: For some problems, especially word problems, physically acting out the scenario or using objects helps in understanding the math concept.
  3. Work backwards: Start from the solution and reverse the operations to find the unknown values, useful for multi-step problems.
  4. Write a number sentence: Translate the problem into a mathematical equation or expression to solve it.
  5. Use a formula: Use relevant formulas (e.g., area = length × width) directly when applicable.

Example:
Problem: John and Jivanti together have 45 marbles. Both lost 5 marbles each, and the product of the marbles they now have is 124. How many marbles did they have initially? Steps:

  • Let John's marbles = xxx
  • Jivanti's marbles = 45−x45-x45−x
  • After losing 5 each: John's marbles = x−5x-5x−5, Jivanti's = 40−x40-x40−x
  • Product equation: (x−5)(40−x)=124(x-5)(40-x)=124(x−5)(40−x)=124
  • Expand: 40x−x2−200+5x=12440x-x^2-200+5x=12440x−x2−200+5x=124
  • Simplify: −x2+45x−324=0-x^2+45x-324=0−x2+45x−324=0
  • Multiply by -1: x2−45x+324=0x^2-45x+324=0x2−45x+324=0
  • Factor: (x−36)(x−9)=0(x-36)(x-9)=0(x−36)(x−9)=0
  • Solutions: x=36x=36x=36 or x=9x=9x=9
    John had 36 marbles, Jivanti had 9 marbles or vice versa.

This combines writing the number sentence and solving the quadratic equation as a method to reach the solution. Similar detailed steps can be applied to various problems.