Download Homework for 3-8 - Stillman Valley High School

Homework for 3-8
p.187 2, 5, 10, 11, 15, 18, 20, 26, 27, 32, 34
3-8 Rewrite Equations &
Formulas
Objective: rewrite equations and formulas, solve for
variables.
Colby says, “A literal
equation is an
equation in which
there are no
numbers, only
letters.”
Literal Equations
2x + 5 = 11 and 6x + 3 = 15 have the
general form ax + b = c.
 ax + b = c is a literal equation.
 Solving a literal equation can sometimes
make solving an equation of the same
form easier.
 Tip: Circle the letter(or variable) that
you are solving for.

Practice
Solve p + qx for x.
x = (r-p)/q
 Now solve 3 + 5x = -7
x = -2
 Write -2x + 3y = 6 so that y is a function
of x.
y = (2/3)x + 2

For a rectangle, A = lw.
Solve the formula for the length.
L =A / w
Use the rewritten formula to find the length of this
rectangle.
A = 351 cm2
13 cm.
L= 27cm.
Irina deposited $650 in a savings account. After
two years her account balance was $682.50.
Find the rate of interest for the two years. Use
the formula A = P(1 + rt), where A is the
account balance, P is principal, r is rate, and t is
time. Rewrite the formula to isolate r and then
solve.
r = (A – P)/ Pt
r = 2.5%