# Math Help - [SOLVED] Agh! Help for a procrastinator!

1. ## [SOLVED] Agh! Help for a procrastinator!

I need help with my homework!

Write the equation of the line passing through (3,7),(1,7), and (7,7)
Find the rate of change between the two points (4,36) and (8,108) and give the unit of measure. x is measured in square yards. y is measured in dollars.
There's more but ill type those up later.

2. equation of the line:

y = mx + b where m is the slope and b is the y intercept

so we know slope = (change in y) / (change in x)

so take two points and calculate slope, then you have m
using m and one point on the line (for x and y) we can solve for b

the rate of change is the slope with units of y / units of x

3. OK! thanks much, i waited too long and my brain froze up. I didn't even notice the matching y's.

Find the coordinates of the vertex of the graph y=|x-2|+4

4. lets first consider the graph of
y = |x|
here we have the vertex at (0,0)

using rules of transformation, we can see that y = |x-2| + 4 is a vertical translation up 4 units and right 2 units

in other words, let f(x) = |x|
then f(x -2) + 4 gives the new equation and again this is a vertical shift up 4 units and a horizontal shift right 2 units

since the old vertex was (0,0), we can deduce that the new vertex underwent the same translation (right 2 units, up 4 units)

thus, the new vertex is located at (2,4)

5. Haha! Dude, you rock.

A heat exchanger is bought by a company for $180,000. It is considered to depriciate over 10 years to a scrap value of$10,000. Assuming a linear model for depriciation, write the equation of its value, V(in dollars), when t years have elapsed after the purchase (t<10).

6. well since its gonna be a linear model we will have the form
y = mx + b
or in the context of the problem V(t) = mt + b
and we know b will be 180 000 so m must be negative

lets try something:

10 000 = V(10)

10 000 = m(10) + 180 000
m(10) = 10 000 - 180 000
m(10) = -170 000
m = -17 000

V(t) = -17 000t + 180 000 ; t<10 where t is the time in years and V is the value in dollars

7. A stock investor has 150,000 to invest in two stocks. APC, Inc. sells for $39.80 per share and Unified Laboratories (UL) sells for 49.70 per share. Write an inequality that restricts an investment of x shares of APC, Inc. and y shares of UL. My response: Er... 8. Originally Posted by jscalalamoboy A stock investor has 150,000 to invest in two stocks. APC, Inc. sells for$39.80 per share and Unified Laboratories (UL) sells for 49.70 per share. Write an inequality that restricts an investment of x shares of APC, Inc. and y shares of UL.

My response: Er...
$39.80x + 49.70y = 150,000$

9. Originally Posted by icemanfan
$39.80x + 49.70y = 150,000$
Wait, is that an inequality?