CPhill

40+25x=15x+30  ........subtract 30 and 25x from both sides

40 - 30  =  15x - 25x

10  =  -10x        divide both sides by  -10

-1 = x

"A" is correct

Here's a link to the graph:

https://www.desmos.com/calculator/nqjyarhcx8

 Hey.....Nataszaa...this is the first time I've tried to link a graph...let me know if you can access it!!!!

"A" is correct, Nataszaa

3ln3 + 3lnc  =

ln 3 ³ + ln c ³ =

ln 27 +  ln c ³ =

ln ( 27 c ³ )

"D"

"B" is correct, Nataszaa

((7w-6)/2)=((8w+3/3)+1    multiply both sides by the common denominator of the two fractions (6)

3[7w - 6 ] = 2[ 8w + 3]  + 6    simplify

21w - 18 = 16w + 6 + 6

21w - 18  = 16w + 12      add 18 to both sides and subtract 16w from both sides

5w = 30      divide both sides by 5

w = [30 / 5]  = 6

4 ^-2 = 1/16

D is correct

3 ln x - 2 ln c =

ln x ³ -  ln c ² =

ln ( x ³/ c ² )

"a" is correct......

Filling what we know, we have

6 = t / (3.3log₈ 7681)    ....and, using the "change of base" rule, we can write

6 = t / [(3.3)log 7681/log8)     .......and multiplying both sides by the denominator on the right, we have

6(3.3)log7681/log8 = t ≈ 85 hrs (rounded)

There you go, Nataszaa