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Question
Make x the subject of the formula a = `1 - (2"b")/("cx" - "b")`. Find x, when a = 5, b = 12 and
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Solution
a = `1 - (2"b")/("cx" - "b")`
⇒ a - 1 = `- (2"b")/("cx" - "b")`
⇒ (a - 1)(cx - b) + 2b = 0
⇒ acx - ab - cx + 3b = 0
⇒ x(ac - c) + b(3 - a) = 0
⇒ xc(a - 1) = -b(3 - a)
⇒ x = `("b"("a" - 3))/("c"("a" - 1)`
Substituting a = 5, b = 12 and c = 2, we get
x = `(12(5 - 3))/(2(5 - 1)`
= `(12 xx 2)/(2 xx 4)`
= 3.
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