i have a quick question with simplifying a variable expression can someone tell me what one is correct? heres the problem 8-12x+20 is simplified to what A)28-12x or B)-12x+28?
yes i can take it from there, idk why u have such a hard time setting these up, 2 more if u dont mind
a 31 inch pipe is cut into two pieces. three times the larger piece is equal to nine more than three times the smaller piece.find the lenth of the smaller peice
^that one i dont even know how to set up
heres the last one
if you reveived a 58 and a 78 on the first two math test, what grade would you need on the next test to have a 70 average
^now that one i got the answer to wich is 74 but i had to do it the long way because i have such a hard time trying to set up these problems
Take the first part of the problem: "a 31 inch pipe is cut into two pieces." So there are two pieces with lengths x and y. Together their length must equal 31 inches. "Together" means addition, so
$\displaystyle x + y = 31$
is your first equation.
Now take the second part of the problem: "three times the larger piece is equal to nine more than three times the smaller piece."
Again, we have the lengths of the two pieces of pipe, x and y. It doesn't matter which is larger; let's say that x is. So
"three times the larger piece..." means 3x,
"is equal to..." means =,
"nine more than three times the smaller piece." means 3y + 9.
Therefore the 2nd equation is
$\displaystyle 3x = 3y + 9$.
You have two equations and two unknowns.
$\displaystyle x + y = 31$
$\displaystyle 3x = 3y + 9$
Can you take it from there?
To find the average of a bunch of numbers, add the numbers up and divide by the number of numbers there are. How many test grades are there? Three: 58, 78, and an unknown number, which we'll call x. Find it's average:heres the last one
if you reveived a 58 and a 78 on the first two math test, what grade would you need on the next test to have a 70 average
$\displaystyle \frac{58 + 78 + x}{3} = 70$
That's the equation. Take it from there!
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