"y varies directly as x" means y = kx
you do not know what k is yet, other than that it is some constant number.
Now plug in the given values, y=12 when x=4, in the equation
12 = 4k
=> k = 3
Now rewrite the equation with the k value you just found
y = 3k
Substitute 18 in place of x
y = 3(18)
y = 54
Considering that the grows at a constant rate we can form an equation where x = how many years after it was planted
and y = its height
Now we just need to find how many feet it grows each year. To do that we just need to compare its height from a certain age to another:
6 years after it was planted : 7 feet,
so x=6 and y = 7
9 years after it was planted: 16 feet
so x= 9 y=16
With thay we can conclude that in 3 years , the tree grew 9 feet. To discover how much the tree grow each year we just nee to divide 9 feet by 3 years which is 3 feet every year.
To write the equatopn now we just need to find the y-intercept which we can discover by setting x to 0:
If in 6 years after the tree was planted it is 7 feet long , we can discover how long it was when it was planted by subtracting 6 years of growth (The slope ) which is 3
7 - 6(years)×3(feet the tree grow each year)
7 - 18 = -11
The tree was -11 feet long when it was planted
which is our y-intercept
( I know it doesnt make sense , but if you apply to a graph it will make more sense )
Now we can make the equation
y = 3x -11
Answer:
2520
Step-by-step explanation:
LCM(4, 7, 8, 9, 10, 12) = 2520
427.0 mm is more precise.
feel free to ask any questions
Answer:
420% of 85 = 357
Step-by-step explanation:
85/x=100/420
(85/x)*x=(100/420)*x - we multiply both sides of the equation by x
85=0.23809523809524*x - we divide both sides of the equation by (0.23809523809524) to get x
85/0.23809523809524=x
357=x
x=357
