Straight

one s. is -14.

We know AX = 2, now solve for CX

2 = CX * 4      | : 4

CX = 0.5

BX/2 = 0.5/BX   | * BX

BX = 1

my bad.

so (- m)² - 4 * 3 * 21 < 0    calculate

     m² - 252 < 0                + 252

     m² < 252                    sqrt both sides

     m < 15.87...               round to the nearest integer (16)

m = 16

16 is the answer.

Hint: For b² - 4ac < 0 it has no real solutions,

then a = 3, b = -m and c = 7.

$\frac{\mbox{Total number of all possible solutions}}{\mbox{Total number of all solutions}}$

You can choose 100 numbers so 

$\frac{n}{100}$ .

There are 50 numbers that are divisible by 2 in the set { 1, 2, 3, ..., 100 }.

In the set { 1, 2, 3, ..., 100 } there are 12 numbers divisible by 8.

Every multiple of 8 is divisible by 2, so (50 - 12 =) 38 possible solutions. (n = 38)

$\frac{38}{100} = \frac{19}{50} = 0.38 = 38\%$

(x, y, z) = (1, 16, 25) is a valid answer.

6x³ - 15x² + 21x

The length of the median of the trapezoid ABCD is 10.