Proportions
Solve: x/3 = 6/9
x = 2
Solve: 4x + 7 - 2x = 5x - 2
x = 3
V = lwh for h
h = V/(lw)
-1/3 x = 7
x = -21
1/2 (x-3) + 1 = 5
*Multiply both sides by 2
x - 3 + 1 = 10
x - 2 = 10
x = 12
x - 3 = 8
x = 11
Solve: 7/x = 5/15
x = 21
Solve: -6x + 15 = 3(x - 1)
x = 2
a + b + c = 180 for b
b = 180 - a - c
(3x + 6) / 3 = -5
x = -7
G = bh + r , solving for b
Their work:
Divided by h: G/h = b + r
Subtracted: G/h - r = b
b = (G-r)/h
Solve: (2x-5)/2 = (4x + 1)/ 3
x = -17/2
Solve: 8(3x-4) = 4(6x - 8)
Infinite Solutions
d/t = r
solve: d
d = rt
-2/3 x + 2 = 10
x = -12
22 gallons of gas cost $28.50. How much will 30 gallons of gas cost?
Student's initial set-up:
22/28.50 = x/30
$38.86
A blueprint scale is 1 inch to 12 feet. The width of a building is 48 feet. What is the width of the building on the blueprint?
x = 4 inches
Solve: 3(2x + 4) = -2(3x - 6)
x = 0
P = 2L + 2W
solve: W
P/2 - L
1/2 x + 1/3x = 10/3
x = 4
6 - 2(x + 3) = -2
Their work:
6 - 2 = 4 so
4(x+3) = -2
4x + 12 = -2 --> x = -14/4
x = 1
Solve: (x-7)/5 = (x+1)/3
x = -13
Solve: 4x-2(3x + 7) = 12 - 3(4x + 5) + 9x
x = 11
a/b = x/y
solve: b
b = (ay)/x
1/5x - 1/3 = -14/6
x = -10
NO ERROR HERE - GOOD LUCK SOLVING
A = 1/2 bh
a. Solve for h
b. Use your new equation to find h if A = 16 and b = 4
a. h = (2A)/b
b. h = 8