PLEASE HELP ME on #57 WITH ALL WORK SHOWN!!

Tmr is my exam pls help...

Explanation:

Recall that quadratic form is ax^2+bx+c.

So we need an x^2 term followed by an x term, then a constant at the end.

It may not look it, but the given equation is nearly in quadratic form.

Rewrite 9^(2x) as (9^x)^2

We get this equivalent equation (9^x)^2 - 2*(9^x) - 3 = 0

From here, let's make w = 9^x. Replace every copy of '9^x' with 'w' and we end up with this new simpler equation: w^2 - 2w - 3 = 0

From here we can use the quadratic formula or factor. I'll factor.

w^2 - 2w - 3 = 0

(w - 3)(w + 1) = 0

w-3 = 0 or w+1 = 0

w = 3 or w = -1

Now we use these values of w to find x

If w = 3, then,

w = 9^x

3 = 9^x

log(3) = log(9^x)

log(3) = x*log(9)

x = log(3)/log(9)

x = log(3)/log(3^2)

x = log(3)/(2*log(3))

x = 1/2

At the last step, we have the log(3) terms cancel.

Repeat for w = -1

w = 9^x

-1 = 9^x

log(-1) = log(9^x)

We run into a problem. The log of any negative number is not a real number output. In other words, 9^x is never negative. Raising any positive number to a real number output leads the result to be positive. Take a look at the graph of y = 9^x to confirm this.

In short, w = -1 is extraneous so it doesn't lead to any x value solution.

So only w = 3 is useful.

Ultimately, the only solution is x = 1/2.

4

step-by-step explanation:

the camry sales+accord sale=828,000. to make it so the two numbers are 18 thousand apart and still equal 828,000, you first need to find out what half of 828,000 is. 828,000/2=414,000. for the two numbers to equal 828,000, you have to add the same amount as you subtract from the middle. in this case, the number is 9,000 because it's half of 18,000. to equal 828,000, you have to add 9,000 to 414,000 for the camry and subtract 9,000 from 414,000 for the accord. 414,000+9,000=423,000.

414,000-9,000=405,000.

423,000+405,000=828,000.

423,000-405,000=18,

hope it