Write a php program that implements the following procedures from class:

• add
  • your function should be named "add" and should add two numbers together
  • it must be able to handle negative numbers
  • use the algorithm from class
• subtract
  • again, name it "subtract"
  • it must be able to handle negative numbers
  • use the algorithm from class
• mult
  • named "mult"
  • must handle negative numbers
  • must use the algorithm from class
• exponential
  • named "exponential"
  • only handle positive exponents, but handle negative bases.
  • must use the algorithm from class

At the very end of your file, add the following code, to make sure everything works:

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echo " 6 + 5 = " . add(6,5); echo " 0 + 2 = " . add(0,2); echo " 8 + -4 = " .add(8,-4); echo " 6 -5 = " . subtract(6,5); echo " 0 -2 = " . subtract(0,2); echo " 8 - -4 = " .subtract(8,-4); echo " 6 * 5 = " . mult(6,5); echo " 0 * 2 = " . mult(0,2); echo " 8 * -4 = " . mult(8,-4); echo " 2 ^^ 5 = " . exponential(2,5); echo " -2 ^^ 5 = " . exponential(-2,5);