Answer:
500 and 900
Step-by-step explanation:
3(x - 300) + 2(x + 100) = 3300 ← distribute parenthesis
3x - 900 + 2x + 200 = 3300
5x - 700 = 3300 ( add 700 to both sides )
5x = 4000 ( divide both sides by 5 )
x = 800
Then
cost of book = x - 300 = 800 - 300 = 500
cost of pen = x + 100 = 800 + 100 = 900
Answer:
what I think the answer is ×=-9
Answer:

Step-by-step explanation:
To isolate r, we're going to need to do some algebraic manipulation.

Multiply both sides by r:

Divide both sides by a:

Hope this helps!
With questions like this (to see if theyre parallel), all you have to do is see if lines have a congruent slope. if yes (ex: 2 and 2), then they are parallel. if the slopes are opposites (ex: 4 and -1/4), then they are perpendicular. If they have no such relation (ex: -3 and 1/7), then they are neither.
with this problem, find the slope by separating the same variable in each equations, like this:
2x + 7y = 6
-2x -2x
7y = -2x + 6
(the second equation is already separated) so now we have
7y = -2x + 6 and 7y = 2x + 6
since -2 does NOT equal 2, these two graphs/lines are NOT parallel.
Hope this helped!