Question

C=-4 D=5 P=2 Q=-1 4cd×10×2p÷50d+20q=??

Answer 1

This is very simple; don't you worry.
     Let's start by breaking down the problem so that it's not overwhelming.
For now, we're only going to focus on the very beginning of the problem -- 4c.
     When a number is next to a letter with no signs in between (in terms of this kind of math), the number is called a coefficient and the letter is called a variable. When you see this in math, it means that the coefficient is being multiplied by the variable. But how do you know what the variable is?
     In other examples of math, you'd have to solve for the variable, but in this case, they already give it to you! Look back at the top... what does C equal? It equals 4! This means that 4c is actually 4x4, or 4(4)!
     What we just did there, changing 4c to 4 multiplied by 4, is called substitution. You just substituted the c with 4. Now you know that to solve this, you need to use the method of substitution. What do you get if you substitute all of the variables with the numbers they equal (as shown above)...?

((4*-4)*5)((10(2*2))/(50(5)))+20(-1). You didn't use parentheses to separate the term /50d + 20q, so I'm assuming that the first part of the problem is only divided by just 50d, and not 50d+20q. In the future, be sure to clarify with parentheses. Anyway...
     ((4*-4)*5)((10(2*2))/(50(5)))+20(-1). Do NOT let this scare you. All the parentheses do is help you see what is being multiplied. All that's left is simple order of operations! You should get -340 as your answer.