Algebra 2

Friday, September 08, 2006

#3.2 continued

Solving Systems of Equations by Elimination

PRACTICE! PRACTICE! PRACTICE! for your Ch. 2 Test!

then....

PRACTICE SOME MORE!

You can do this! I expect everyone to get A's on Monday!

Have a PG-13 weekend!

kierra,

what do problems 6, 7, and 15 say?

By msichan, at Sunday, September 10, 2006 10:32:00 AM
kierra,

Write in standard form an equation of the line passing through the given point with the given slope.

#6. slope=9; (5, -1)

write your eqn in point-slope form first:

y - y1 = m (x - x1)
y - (-1) = 9 (x - 5)
y + 1 = 9 (x - 5)

then convert that to slope-intercept form:

y = mx + b

y + 1 = 9x - 45

minus one to both sides gives you:

y = 9x - 46

now convert that to standard form:

Ax + By = C

minus 9x from both sides to get:

-9x + y = -46 or
9x - y = 46

Now you try for number 7:

#7. slope=5/7; (-4, -5)

And I wanted to know the answers to number 15 which says:
A leaky valve on the water meter overcharges the residents for one gallon of water in every 2 1/2 months. The overcharged amount w varies directly with time t.
a. Find the equation that models this direct variation.

w = kt
1 = k(2.5)
1 = k(5/2)
2/5 = k

w = 2/5t

b. How many months it will take for the residents to be overcharged for 8 gallons of water?

8 = 2/5t
8(5/2) = t
20 = t
t = 20 months

By msichan, at Sunday, September 10, 2006 2:17:00 PM