5. Write the number 81 as a power with a base of 3 and a base of 9.
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Answer:
-5
Step-by-step explanation:
Moving all terms of the quadratic to one side, we have
.
A quadratic has one real solution when the discriminant is equal to 0. In a quadratic , the discriminant is
.
(The discriminant is more commonly known as , but I changed the variable since we already have a
in the quadratic given.)
In the quadratic above, we have ,
, and
. Plugging this into the formula for the discriminant, we have
.
Using the distributive property to expand and simplifying, the expression becomes
Setting the discriminant equal to 0 gives
.
We can then solve the equation as usual: first, divide by 2 on both sides:
.
Squaring both sides gives
,
and subtracting 5 from both sides, we have