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Algebra 1
Section 3.6
Literal Equations and
Formulas
Solve the equation for the indicated variable.
1. 2y + x = 4, for x
-2y
-2y subtract 2y from both sides
x = -2y + 4
2. 2y + x = 4, for y
-x -x
2y = -x + 4
2y = -x + 4
2
2
2 divide both sides by 2
y = -x + 2
2
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3. 3b – (-2a) + 9 = -7, for a
3b + 2a + 9 = -7 eliminate double sign
-9
-9 subtract 9 from both sides
3b + 2a = -16
-3b
-3b subtract 3b from both sides
2a = -3b – 16
2a = -3b - 16
2
2
2 divide both sides by 2
a = -3b - 8
2
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4. 5m + 3n + 4 = -2n, for n
-3n
-3n subtract 3n from both sides
5m + 4 = -5n
5m + 4 = -5n
-5
-5
-5 divide both sides by -5
n= -m - 4
5
5. 12t – 2(3s) = 5t, for s
12t – 6s = 5t multiply -2(3s)
-12t
-12t subtract 12t from both sides
-6s = -7t
-6s = -7t
-6
- 6 divide both sides by -6
s = 7t
6
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6. Area of a Triangle
solve for h
2 A = 1 bh
2
2
multiply both sides by 2
2A = bh
2A = bh
b
b
h = 2A
b
divide both sides by b
7. Volume of a Rectangular Prism
V = LWH solve for L
V = LWH
WH
WH divide both sides by WH
L = V
WH
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8. S = C + rC solve for C
S = C(1 + r) factor C out of right side (opposite of distributive property)
S = C(1 + r)
1+r
1+r
divide both sides by 1+r
C = S
1+r
9. A = P + Prt solve for r
-P -P
subtract P from both sides
A – P = Prt
A – P = Prt
Pt
Pt divide both sides by Pt
r = A–P
Pt
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10. A water tank in the shape of a rectangular prism is 12 feet long
and 3 feet wide. The tank has 9.4 ft3 of water. How deep is
the water in the tank?
3 ft
12 ft
V = lwh
9.4 = 12(3)(h)
9.4 = 36h
h = .26 ft
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11. A rectangle is 1.5 times as long as it is wide. The perimeter
of the rectangle is 75 inches. Find the width of the rectangle.
1.5x
x
x
1.5x
x + 1.5x + x + 1.5x = 75
5x = 75 combine like terms
x = 15 inches
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Solve each equation.
1.) Solve for L:
P = 2L + 2W
2.) Solve for h:
V = π r2 h
3.) Solve for L:
S = L – rL
4.) Solve for P:
A = P(1 + r)t
Algebra 1
Section 3.6
Assignment
Solve each equation.
5.) 4t – 1 = 7
6.) s – 35 + 9 = 10 – s
7.) 3(x – 1) = x + 9


8.) 1  1 a  4  8  3 a

2  2
4

Evaluate each expression.
9.) 4V – 3H + 9, when V = ½ and H = 4
10.) 9x + 36 – 4y, when x = 2 and y = 14
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© Mr. Sims