Identify the form: Identify the form of the limit.We need to find the limit of the function (4x+28−4)/(x+3) as x approaches −3. Let's first substitute x=−3 into the function to see if the limit can be directly calculated.x→−3lim(4x+28−4)/(x+3)=(4(−3)+28−4)/((−3)+3)=(−12+28−4)/0=(16−4)/0=(4−4)/0=0/0This is an indeterminate form, so we cannot directly calculate the limit. We need to use algebraic manipulation to simplify the expression.
Apply algebraic manipulation: Apply algebraic manipulation to simplify the expression.To eliminate the indeterminate form, we can multiply the numerator and the denominator by the conjugate of the numerator. The conjugate of 4x+28−4 is 4x+28+4.limx→−3x+34x+28−4⋅4x+28+44x+28+4
Perform the multiplication: Perform the multiplication.Now, we multiply the numerators and the denominators separately.Numerator: (4x+28−4)(4x+28+4)=(4x+28)−16Denominator: (x+3)(4x+28+4)
Simplify the expressions: Simplify the resulting expressions.Simplify the numerator:(4x+28)−16=4x+12Simplify the denominator:We leave it as is for now: (x+3)(4x+28+4)Now the limit expression looks like this:limx→−3(x+3)(4x+28+4)4x+12
Factor out common terms: Factor out common terms.We notice that the numerator has a term 4x+12 which can be factored as 4(x+3).limx→−3(x+3)(4x+28+4)4(x+3)Now we can cancel out the (x+3) term in the numerator and denominator, as long as x=−3.limx→−3(4x+28+4)4
Evaluate the limit: Evaluate the limit.Now that the expression is simplified, we can substitute x=−3 to find the limit.limx→−3(4x+28+4)4=(4(−3)+28+4)4=(−12+28+4)4=(16+4)4=4+44=84=21
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