Please explain if you can thanks
2007-08-12 03:02:02 · 9 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
Let numbers be x and y
x + y = 84
4x + 9 = y
x + (4x + 9) = 84
5x = 75
x = 15
y = 69
2007-08-16 02:09:41 · answer #1 · answered by Como 7 · 0⤊ 0⤋
Let x be the first number.
Thus, 4x + 9 will be your second number because of the sentence "the second is 9 more than 4 times the first".
Equation: x + (4x + 9) = 84. (Because the sum of first and second number is 84.)
Solve for x:
5x + 9 = 84
5x = 75
x = 15
Therefore, your first number is 15 while your second number is 69.
2007-08-12 03:15:38 · answer #2 · answered by valkyrie 1 · 1⤊ 0⤋
x+4x+9=84 *This would be the starting equation*
5x+9=84 *Combine like terms- the two x's*
5x=75 *Subtract the 9 from 84*
x=15 *Divide 75 by 5 to leave the x alone and find out what x is*
4(15)+9=69
The two numbers are 15 & 69
2007-08-12 03:14:10 · answer #3 · answered by Rachael 3 · 1⤊ 0⤋
ok so one number can be called x then the other number is 4x +9
so
x + 4 x+9 = 84
combining
5x + 9 = 84, or
5x = 75
x = 15, 4 x+9 = 69
2007-08-12 03:12:36 · answer #4 · answered by tfloto 6 · 0⤊ 0⤋
let x = first number
let y = second number
then equation 1 is: x + y = 84
and
equation 2 is: y = 4 * x +9 (y is 9 more than 4 times x)
therefore
y = 4 x + 9
now substitute your new definition of y into equation 1
x + (4x+9) = 84
add like terms
5x + 9 = 84
subtract 9 from both sides
5x = 75
solve for x
x = 15
use equation 1 to find y
x+y=84
15 + y = 84
solve for y
y = 69
check it:
y is 9 more than 4 times x?
69 is 9 more than 4 times 15?
69 is 9 more than 60?
Yup!
2007-08-12 03:22:43 · answer #5 · answered by jc42 2 · 0⤊ 0⤋
let
x=1st no.
4x+9 = 2nd no.
x+4x+9=84 (add x+4x and transpose 9 on the other side)
5x=84-9 (subtract 9 from 84)
5x=75 (divide both sides by 5 to remove 5 from x)
x=15 (here is your 1st no.)
for the 2nd no. just replace x with 15
4x + 9
4(15) + 9
60 + 9
=69 (here is your 2nd no)
to check add teh 2 numbers
15 + 69 = 84
=)
2007-08-12 03:17:09 · answer #6 · answered by DivineMeowMeow 2 · 0⤊ 0⤋
Turn the words into math adn you get...
x + y = 84....equation 1
y = 9 + 4x....equation 2
put equation 2 in for equation 1, you get...
x + 9 + 4x = 84
5x = 75
x = 15, y = 69
(after finding x you can find y by plugging X in either of the two equations b/c they both are connected)
=D
2007-08-12 04:09:52 · answer #7 · answered by LIFE HATER 1 · 0⤊ 0⤋
x+y = 84
x be the first #
y be the 2nd #
y = 4x + 9
x+y = 84
x + 4x + 9 = 84
5x = 84 - 9
5x = 75
x = 15
y = 4x + 9
y = 4(15) + 9
y = 60 + 9
y = 69
2007-08-12 03:17:39 · answer #8 · answered by Enginurse 2 · 0⤊ 0⤋
first number = x
second number = 4x + 9
(x) + (4x + 9) = 84
5x + 9 = 84
5x = 75
x = 15
first number = x = 15
second number = 4x + 9 = 69
2007-08-12 03:11:19 · answer #9 · answered by Anonymous · 0⤊ 0⤋