[solving equations for a variable][section 18]
(1.) C = ∏d solve for d
C = ∏d here is the problem
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∏ ∏ divide each side by ∏
C/∏ = d cancel
result:
d = C/∏
(2.) A = bh solve for b
A = bh here is the problem
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h h
divide each side by h
A/h = b cancel
result: b = A/h
(3.) P = 2L + 2w solve for w
-2L -2L subtract 2L from each side
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P - 2L = 2w
subtract
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2 2
divide each side by 2
(P - 2L)/2 = w cancel
result: w = (P - 2L)/2
(4.) A = (1/2)bh solve for h
A = (1/2)bh here is the problem
2* A = 2*(1/2)bh multiply each side by 2
2A = bh cancel
___ ____
b b
divide each side by b
2A/b = h cancel
result: h = 2A/b
(5.) i = prt solve for t
i = prt here is the problem
___ _____
pr
pr divide each side by pr
i
____ = t cancel
pr
i
result: t = _______
pr
(6.) C = (5/9)(F - 32) solve for F
(9/5)C = (9/5)(5/9)(F - 32) multiply each side by 9/5
(9/5)C = F - 32 cancel
+ 32 + 32 add 32 to each side
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(9/5)C + 32 = F add
result: F = (9/5)C + 32
(7.) a + b + c = 180 solve for b
-a - a subtract a from each side
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b + c = 180 - a subtract
-c - c
subtract c from each side
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b = 180 - a - c subtract
result: b = 180 - a - c
(8.) 2n + 5a = 8a solve for n
-5a -5a
subtract 5a from each side
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2n
= 3a subtractS
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2 2
divide each side by 2
3a
n = ______ cancel
2
3a
result: n = ______
2
(9.) a(b + n) = c solve for b
a(b + n) = c here is the problem
ab + an = c multiply thru parentheses
-an - an
subtract an from each side
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ab =
c - an subtract
_____ ________
a a divide each side by a
b = (c - an)/a cancel
result: b = (c - an)/a
(10.) A = (1/2)h(b1 + b2) solve for b1
A = (1/2)h(b1 + b2) here is the problem
2A = 2(1/2)h(b1 + b2) multiply each side by 2
2A = h(b1 + b2) cancel
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h h divide each side by h
2A/h = b1 + b2 cancel
-b2 - b2 subtract b2 from each side
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(2A/h) - b2 = b1 subtract
result: b1 = (2A/h) - b2