Ming is given the following function and asked to find b. f(x)=15(b)x if f(4) = 1215, what is one possible value of b?

3

Step-by-step explanation:

if you did this on prepworks its 3.

1215=15(b)4  

121515=(b)4

81=b4

92=b4

(32)2=b4

34=b4

b = ±3

Step-by-step explanation:

f(x) = 15(b)x

f(4) = 1215

15(b)4 = 1215

(15)(4)b = 1215

60b = 1215

60b / 60 =  1215 / 60

b = 20.25

Check the answer

15 * 20.25 * 4 = 1215

9514 1404 393

  3)  D

  4)  D

  5)  B

  6)  B

Step-by-step explanation:

3) A "Pythagorean triple" is a set of 3 integers that could be the sides of a right triangle. The only triangle shown with integer side lengths is choice D.

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5) The only triangle for which the square of the hypotenuse is the sum of the squares of the other two sides is choice D.

  11² +2² = (5√5)²

  121 + 4 = 125

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6) The lengths of sides of each right triangle are 2/3 of those of choice D in problem 4. That is, they are a 7-24-25 triangle, multiplied by 2. That means the height is 24·2 = 48, and the area is ...

  A = 1/2bh

  A = 1/2(28 m)(48 m) = 672 m² . . . . matches choice B

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7) The side lengths of a 30-60-90 triangle have the ratios 1 : √3 : 2. That is, the short leg is half the hypotenuse, a fact stated in A and D. Those true statements make it clear that statement B is false.