Twice a number is 4 less than a second number, while 5 times the 1st number is 3 less than twice the 2nd number. Find the two numbers.
2007-08-04 19:13:29 · 3 answers · asked by Michael Ray G 1 in Science & Mathematics ➔ Mathematics
ok, let's call the first digit x and the second digit y.
we know that 2x = y-4 and that 5x = 2y - 3
What I'd do here is multiply both sides of the first equation by -2 then add them together.
so we get -4x = -2y + 8 and 5x = 2y - 3
adding them gives you x = 5.
Now substituting 5 for x in the first equation gives you 10 = y-4, making y = 14.
So the two numbers are 5 and 14. Done!
2007-08-04 19:21:26 · answer #1 · answered by ǝɔnɐs ǝɯosǝʍɐ Lazarus'd- DEI 6 · 0⤊ 0⤋
Let x = 1st no., y = 2nd no.
Equation 1:
y - 4 = 2x
y = 2x + 4
2nd equation:
5x = 2y - 3
2y = 5x + 3
y = 2.5x + 1.5
1st & 2nd equation:
2x + 4 = 2.5x + 1.5
0.5x = 2.5
x = 5
1st equation (substitute x with 5):
y = 2(5) + 4
y = 10 + 4
y = 14
Answer: 1st no. = 5, 2nd no. = 14
Proof:
2(5) = 14 - 4
10 = 10
5(5) = 2(14) - 3
25 = 28 - 3
25 = 25
2007-08-08 02:52:07 · answer #2 · answered by Jun Agruda 7 · 2⤊ 0⤋
x = 1st number
y = 2nd numberr
2x = y - 4
5x = 2y-3
-4x = -2y +8
x= 5
2(5) = y -4 --> y = 14
2007-08-05 02:33:15 · answer #3 · answered by ironduke8159 7 · 0⤊ 0⤋