Because there are no parentheses, I'm assuming you're asking for how to factor this using the GCF, which can be done like so:
9−12x+6y
Factor a 3 out of this expression.
3(3 - 4x + 2y)
The expression has been simplified using the distributive property in reverse.
Multiply first equaton by 2 and add to the other equation
6x+6y=12
<u>5x-6y=15 +</u>
11x+0y=27
11x=27
divide both sides by 11
x=27/11
sub back
3x+3y=6
divide both sides by 3
x+y=2
(27/11)+y=2
2 and 5/11+y=2
minus 2 and 5/11 both sides
y=-5/11
x=27/11
y=-5/11
(27/11,-5/11)
He had 40 pencils left after he gave away 8, so originally he had 40 + 8 pencils, which is 48.
Now, he bought 4 packages, which had a total of 48 pencils, so divide 48 by 4, which is 12. He had 12 pencils in each package.
To determine the solution arithmetically, first add 8 to 40, then divide 48 by 4.
To determine the solution algebraically, set up and solve the equation 40 = 4x - 8.
Each package contained 12 pencils.
Hope this helps
