Solve the equation 4s2+32s=60 by completing the square
1 answer:
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Answer:
(c) x = 2 and x = -8
Step-by-step explanation:
The rules of logarithms let you rewrite this as a quadratic equation. That equation will have two (2) potential solutions. We know from the domain of the log function that any negative value of x will be an extraneous solution.
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The rules of logarithms that apply are ...
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<h3>take antilogs</h3>We can rewrite the equation so that only one logarithm is involved. Then we can take antilogs.
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<h3>solve the quadratic</h3>Adding (6/2)² = 9 to both sides will "complete the square."
16 +9 = x² +6x +9 . . . . . . . add 9
25 = (x +3)²
±√25 = x +3 = ±5 . . . . . take the square root(s)
x = -3 ±5 = {-8, +2}
The two potential solutions are x = 2 and x = -8.
Solve for x by cross multiplying then isolating the variable:
cross multiply
15x=90 Isolate the variable
x=6
Solve for y by cross multiplying then isolating the variable:
cross multiply
9y=90 Isolate the variable
y=10
15x=90 Isolate the variable
x=6
Solve for y by cross multiplying then isolating the variable:
9y=90 Isolate the variable
y=10