Question

Four times a number minus twice another number is -8. The sum of the two number is 19.Find the numbers

Answer 1

1. To solve this exercise, you must make a system of equations.

 2. You have that four times a number minus twice another number is -8:

 4x-2y=-8

 3. And the sum of the two number is 19:

 x+y=19

 4. As you can see, you have two equations:

 4x-2y=-8   (i)
 x+y=19     (ii)

 5. Let's clear the "x" from the equation (ii):

 x=19-y

 6. Now, you need to susbtitute x=19-y into the equation (i):

 4x-2y=-8
 4(19-y)-2y=-8
 76-4y-2y=-8
 76-6y=-8
 -6y=-8-76
 -6y=-84
 y=-84/-6
 y=14

 7. You must susbstitute y=14 into the equation (ii) and clear "x":

 x+y=19
 x+14=19
 x=19-14
 x=5

 The answer is: 5 and 14