one number is 9 more twice another number. If the sum of the number 129 find both numbers.

Answer 1

a = 2b + 9

a + b = 129

Suuuubstitute!

2b + 9 + b = 129

3b = 120

b = 40

a = 2(40) + 9

a = 89

Answer 2

identify the variables

x= 1st number

y = 2nd number

You will make a system of equations

one number is 9 more than twice the other number

x = 2y+9

the sum of the numbers is 129

x+y= 129

now here is the system: x= (2y+9)

x+y=129

I would use substitution method and replace what x equals into the second equation. So now it should look like this:

(2y+9) +y = 129

now combine like terms

3y+9=129

Solve for y:

3y=120

I’ll let you finish that equation.

Once you find y plug it into X+y=129 and then you’ll x find also.

I hope this helped you get started! Have a great day!

Mrs. S

Answer 3

X=9+2Y

X+Y=129

X=129-Y

129-Y = 9+2Y

3Y = 120

Y = 120/3 = 40

X= 129-Y = 129-40 = 89

the numbers are 89 and 40