6x-4y=-14
2(-3x-3y=12)
6x-4y=-14
-6x-6y=24
-10y=10
Divide both sides by 10
-1y=1 divide by -1
y=-1
6x-4(-1)=-14
6x+4=-14
-4 -4
6x=-18
Divide both sides by 6
x=-3
Assuming that the interest rate in each case is the same, the only factors that come into play are the length of time, and the accessibility of the money. The longer the money is left alone, the more money it will accrue, meaning the first option "saving for retirement in 20 years" is the best option. The two below it are a shorter length of time and will therefore accrue less, and the final option is less profitable because withdrawing from the account would decrease the total interest earned.
Lovely algebra.
Given that Jack scored a number that is 17 more than Yazid's number,
1) Jack = x + 17
So we know yazid has 17 less than jack so we minus 17 from jack's equation. (x + 17) - 17 = x
2) Yazid = x
It is also given that Susan scored twice of Yazid's score therefore we can multiply Yazid's equation.
3) Susan = 2(x)
= 2x
Finally, it tells us that everyone's score added up is 161 therefore we can write the whole equation like this:
4) (x+17)+(x)+(2x) = 161
Now simplify
5) 4x + 17 = 161
Solve x by subtracting 17 from both sides.
6) 4x = 161-17
4x = 144
So x= 144/4
X=36
Now remember, Jack's equation was (x+17) so we are now able to substitute x into the equation. Since we found x = 36,
Jack = (36 + 17)
Which equals to 53.
So jack's score was 53!