Homework Help Forum: Elementary Set Theory

Posted by Matrix School 1 on Thursday, July 9, 2009 at 2:47pm.

An operation * is defined by the relation x*y = 5x + 3y - 4xy Evaluate (3*2)*4

• Elementary Set Theory - bobpursley, Thursday, July 9, 2009 at 2:54pm

  well, 3*2= 15+6-24=-3 check that then -3*4 must be =-15+12+48=45 check that.

  
  

• Elementary Set Theory - Marth, Thursday, July 9, 2009 at 2:57pm

  Everywhere you see the * symbol, use the function 5x + 3y - 4xy, where x and y are the numbers to either side of the * symbol. Order of operations still applies: start within the parentheses first. 3*2 = 5(3) + 3(2) - 4(3)(2) 3*2 = 15 + 6 - 24 3*2 = -3 Now you have (-3)*4 -3*4 = 5(-3) + 3(4) - 4(-3)(4) -3*4 = -15 + 12 + 48 -3*4 = 45 So the answer is 45.

  
  

Answer this Question

First Name:
School Subject:
Answer: