How many positive numbers from 1 to 999 have the sum of
their digits equal to 8?
for ex. the sum of digits in the numbers 62, 431, are equal to 8.

45 positive numbers have the sum of  their digits equal to 8

Step-by-step explanation:

given data

number = 1 to 999

sum n = 8

to find out

positive numbers

solution

we will choose number by this formula

(n+1) (n+2) / 2

here n is 8

so put this value we get number that

positive numbers = (n+1) (n+2) / 2

positive numbers = (8+1) (8+2) / 2

positive numbers = 90 / 2

so 45 positive numbers have the sum of  their digits equal to 8

x= -3 and

step-by-step explanation:

to find the roots of a cubic, use division or factoring to find the factors then set equal to 0. as this is a difference of cubes, it factors into

where a is the cube root of .

here   this is 27 and the cube root of 27 is 3. so we write using the form:

.

set each factor to 0 and solve for x.

x-3=0

x=3

the quadratic expression does not factor and must be solved using the quadratic formula.

where a = 1, b=3, and c=9

this cubic has two complex roots.

if farmer matt works for 8 hours a day, how many days will it take him to completely plant 12 rows of crops? each batch of cookies needs 3/4 cups of sugar.

step-by-step explanation: