Question

The sum of 3 numbers is 45. The first number is 4 times the second, while the third is 9 more than the second. Create an equation and solve.

Answer 1

x = 2nd number

4x + x + (x + 9) = 45

6x + 9 = 45

6x = 36

x = 6

Answer 2

x+y+z=45
x=4y
z=y+9

4y+y+y+9=45
6y=36
y=6
...

Answer 3

a = first number

b = second number

c = third number


a = 4 b

c = b + 9


a + b + c = 45

4 b + b + b + 9 = 45

6 b + 9 = 45 Subtract 9 to both sides

6 b + 9 - 9 = 45 - 9

6 b = 36 Divide both sides by 6

6 b / 6 = 36 / 6

b = 6


a = 4 b

a = 4 * 6 = 24


c = b + 9

c = 6 + 9 = 15


First numer 24 , second number 6 , third number 15


a + b + c = 45

24 + 6 + 15 = 45

45 = 45

Answer 4

thank you now i understand , i got the answer but i made a mistake on the equation