Answer:
y = 6
Step-by-step explanation:
Given that y varies directly with x then the equation relating them is
y = kx ← k is the constant of variation
To find k use the condition y = 3 when x = 9, then
k = 
= 
= 
, thus
y = x ← equation of variation
When x = 18, then
y = × 18 = 
= 6
It helps to think of a simpler problem. Let's say mpg is 20 and 10% higher on a smooth road.
How many miles will you get with one gallon on a regular road?
How many more miles will you get on a smooth road? 10% more, right? How much is that?
OK - so you've now solved a simpler problem. Use the exact some process to solve your, more complicated, problem.
Two inequalities that represent this situation:
First one is w>5 because they are planting more than 5 acres with wheat, or w.
Second is w+c
27 because the amount of wheat + corn (w+c) has to be less than or equal to 27.
Step-by-step explanation:
-13=4v+8-7v
-13-8=-3v
3v=21
v=7
Answer:
x=-27/7, y=-5/7. (-27/7, -5/7).
Step-by-step explanation:
-4x+9y=9
x+3y=-6
-------------
-4x+9y=9
-3(x+3y)=-3(-6)
-----------------------
-4x+9y=9
-3x-9y=18
----------------
-7x=27
x=-27/7
-27/7+3y=-6
3y=-6-(-27/7)
3y=-6+27/7
3y=-15/7
y=(-15/7)/3
y=(-15/7)(1/3)=-15/21=-5/7
