Q. Perform the following operation and express in simplest form.x2+7x−18x2−81÷9x2x−9Answer:
Identify Operation and Rewrite: Identify the operation to be performed and rewrite the division as multiplication by the reciprocal.The given expression is a division of two fractions, which can be rewritten as the multiplication of the first fraction by the reciprocal of the second fraction.(x2−81)/(x2+7x−18)×(9x2)/(x−9)
Factor Numerator and Denominator: Factor the numerator and denominator of the first fraction where possible.The numerator x2−81 is a difference of squares and can be factored as (x+9)(x−9).The denominator x2+7x−18 can be factored by finding two numbers that multiply to −18 and add to 7, which are 9 and −2.So, x2+7x−18factors as (x+9)(x−2).Now the expression is (x+9)(x−2)(x+9)(x−9)×x−99x2.
Cancel Common Factors: Cancel out common factors in the first fraction.The (x+9) terms cancel out in the numerator and denominator of the first fraction.Now the expression is x−2x−9×x−99x2.
Multiply Remaining Terms: Cancel out the common (x−9) terms in the resulting expression.The (x−9) terms cancel out in the numerator of the first fraction and the denominator of the second fraction.Now the expression is (x−2)1×19x2.
Check for Simplification: Multiply the remaining terms.Multiplying the remaining terms gives us x−29x2.
Check for Simplification: Multiply the remaining terms.Multiplying the remaining terms gives us x−29x2.Check for any further simplification.The expression x−29x2 cannot be simplified further as there are no common factors to cancel out.
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