Question 1021491
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{{{(a+b)/b=c/d}}} . Multiply each side by b.
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{{{a+b=(bc)/d}}} . Multiply each side by d.
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{{{da+db=bc}}} . Subtract db from each side.
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{{{da=bc-bd}}} . Factor b from right side.
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{{{da=b(c-d)}}} . Divide each side by (c-d).
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{{{(da)/(c-d)=b}}}
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