Question
Factor the expression
3(5−x)(5+x)
Evaluate
75−3x2
Factor out 3 from the expression
3(25−x2)
Solution
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Evaluate
25−x2
Rewrite the expression in exponential form
52−x2
Use a2−b2=(a−b)(a+b) to factor the expression
(5−x)(5+x)
3(5−x)(5+x)
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Find the roots
x1=−5,x2=5
Evaluate
75−3x2
To find the roots of the expression,set the expression equal to 0
75−3x2=0
Move the constant to the right-hand side and change its sign
−3x2=0−75
Removing 0 doesn't change the value,so remove it from the expression
−3x2=−75
Change the signs on both sides of the equation
3x2=75
Divide both sides
33x2=375
Divide the numbers
x2=375
Divide the numbers
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Evaluate
375
Reduce the numbers
125
Calculate
25
x2=25
Take the root of both sides of the equation and remember to use both positive and negative roots
x=±25
Simplify the expression
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Evaluate
25
Write the number in exponential form with the base of 5
52
Reduce the index of the radical and exponent with 2
5
x=±5
Separate the equation into 2 possible cases
x=5x=−5
Solution
x1=−5,x2=5
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