3D - 2

A Problem with fractions?

I am reading an example of a system of equations problem in a textbook, and they are combining like terms and it doesn't explain how they got their result, and I don't have a clue. I need help understanding. They have (equation 1): d+t = 749 (equation 2): t = 1/4d-1 Then working it out a little. d+t = 749 d+1/4d-1 = 749 (substituting 1/4d-1 for t) then the next line says: 5/4d-1 = 749 Combining like terms I don't understand how to combine the like terms and how it comes out to 5/4d-1 I've been staring at this for 15 minutes and can't figure it out. Please help.

Public Comments

1. Like terms are numbers multiplied by the same variable. In other "words": 2b and 4b are like terms. 1c and 2c are like terms. 3 and 5 are like terms. 3c^2 + 2c are not like terms. 2c and 4b are not like terms. 3p and 3 are not like terms. When you are adding like terms, you just add the coefficients. 2b + 4b = 6b. 1c + 2c = 3c. Remember that when the coefficient is 1, you can just write the variable normally. c + 2c = 3c. This is because: 2c = c + c. 3c = c + c + c. So... 2c + 3c = c + c + c + c + c = 5c. In your math problem, d and 1/4d are like terms. Remember that we can also write just plain d as 1d. 1d + 1/4d = 5/4d. The -1 doesn't have any like terms, so we can't do anything with it. Hope this helps!