Respuesta :
x=smaller number
y=larger number
x+y=12
y=3x-6
Let's begin with the first equation...
x+y=12
Let's substitute...
x+(3x-6)=12
4x-6=12
Let's add 6 to both sides as we proceed to isolate x...
6+4x-6=12+6
4x=18
Let's divide both sides by 4...
(4x)/4=18/4
x=9/2=4.5---smaller number
12-4.5=7.5s larger number
Answer:
The sum of the two numbers is -18.
Step-by-step explanation:
You can work your way through the problem starting with ...
1/3 the difference of two numbers is 12
Since 3 times 12 is 36, the difference of the two numbers is 36.
Then you are told ...
the larger number is 9
so the smaller number will be 9 less the difference, or ...
smaller number = 9 - 36 = -27.
Now, you know both numbers, so you know there sum is ..
9 + (-27) = -18 . . . . . sum of the two numbers
_____
You can work it also using L for the larger number, D for the difference. Then the smaller number is (L-D) and the sum is ...
sum = L + (L -D) = 2L - D
Filling in the values given for the larger number and the difference, you have ...
sum = 2·9 - 3·12 = 18 -36 = -18 . . . . . as before