2n=n-5 subtract n from both sides
n=-5
check...
2(-5)=(-5)-5
-10=-10
<span>2y = x + 3 then x = 2y - 3
5y = x - 7 then x = 5y + 7
so
</span>2y - 3 = 5y + 7
2y - 5y = 7 + 3
-3y = 10
y = -10/3
y = -3 1/3
<span>2y = x + 3
</span>2 (-10/3) = x + 3
-20/3 - 3 =x
-29/3 = x
-9 2/3 =x
or
x = -9 2/3
solutions: x = -9 2/3 and y = -3 1/3
3,3,2 these are the primes of 18
15. 5 times 3 is 15.
If you check, 15 divided by 3 is 5(red cars).
