Question 209803
the second of three numbers is 8 more than the first, and 
the third number is 3 less than 3 times the first.
 if the third number is 15 more than the second, find the three numbers.
:
Three numbers: x, y, z, try to get all three numbers in terms of x:
:
Write an equation for each statement:
:
"the second of three numbers is 8 more than the first,"
y = x + 8
:
"the third number is 3 less than 3 times the first."
z = 3x - 3
:
"the third number is 15 more than the second,"
z = y + 15
Substitute (x+8) for y
z = (x+8) + 15
z = x + 23
Replace z with 3x - 3
3x - 3 = x + 23
3x - x = 23 + 3
2x = 26
x = {{{26/2}}}
x = 13 is the 1st number
:
y = x + 8
y = 13 + 8
y = 21 is the 2nd number
:
z = x + 23
z = 13 + 23
z = 36 is the 3rd number