Answer:
x - 15 ÷ 2
Step-by-step explanation:
Since it wants you to find the half of your answer after you find the difference, be sure to leave the two at the end of your equation. With that said, let's move into finding out what "the difference of a number and fifteen is". Whenever they tell you 'a number', it means they want you to put a variable, such as x, since you do not know the number and it could be any number. Now, the "difference" of something usually means...you guessed it, subtraction! Now that you've decoded your equation, you now know it means that x - 15 is the first part, and you can now put the one half right after it.
If this is confusing, I can explain further. :D
I'm taking the liberty of editing your function as follows: <span>w=4r^2+6s^2, where I use " ^ " to indicate exponentiation.
The partial of w with respect to r is 8r. That with respect to s is 12s.</span>
Answer: 
Step-by-step explanation:
Given
The ratio of mixture of sand and cement is 5:3
If the total volume of mixture is 
Suppose there is 5x and 3x cubic centimeter of sand and cement respectively i.e.

Sand 
So, there is
of sand in the mixture
Answer:
(- 1, 1 )
Step-by-step explanation:
Given the 2 equations
2x - y = - 3 → (1)
x + y = 0 → (2)
Adding the 2 equations term by term will eliminate the term in y, that is
3x = - 3 ( divide both sides by 3 )
x = - 1
Substitute x = - 1 into either of the 2 equations and solve for y
Substituting into (2)
- 1 + y = 0 ( add 1 to both sides )
y = 1
Solution is (- 1, 1 )