Answer:
(x, y) = (-5, 18)
Step-by-step explanation:
You have done the first two steps.
<h3>3.</h3>7x +2(3 -3x) = 1 . . . . . equation with y substituted
7x +6 -6x = 1 . . . . . . . eliminate parentheses using the distributive property
x = -5 . . . . . . . . . . . . . subtract 6 from both sides, collect terms
<h3>4.</h3>y = 3 -3(-5) . . . . . . . . use the substitution equation to find y
y = 18
The solution is (x, y) = (-5, 18).
Answer:
The length of the shadow is increasing with the rate of 1.5 feet per sec
Step-by-step explanation:
Let AB and CD represents the height of the lamppost and child respectively ( shown below )
Also, let E be a point represents the position of child.
In triangles ABE and CDE,
( right angles )
( common angles )
By AA similarity postulate,
∵ Corresponding sides of similar triangles are in same proportion,
We have, AB = 12 ft, CD = 4 ft, BE = BD + DE = 6 + DE,
Now, the speed of walking = 2 mph =
Note: 1 mile = 5280 ft, 1 hour = 3600 sec
Thus, the time taken by child to reach at E
= 2.045 hours
Hence, the change rate in the length of shadow
= 1.5 ft per sec.
