1. ## Solving coefficients

Equations
1. 10 = 121a+11b+c
2. x = -b/2a
3. 35 = -b^2/4a + c
4. b = 4.8233-22a

There are 4 unknowns and 4 equations. After numerous attempts of trying to find a i could really use some help. The actual value of a is -0.233 or part there of. Here is my best attempt, i cant see where i went wrong.

equation 3. c = 35 + b^2/4a

10= 121a+11b+35+b^2/4a
10=121a+53.0563-242a+35+ (9.6466-212.2252+484a^2 all over 4a)
40a = 212.2252a-484a^2+140a+9.6466-212.2252a+484a^2
40a=140a+9.6466
100a= - 9.6466
a = -0.096466

2. Originally Posted by bubbles73
Equations
1. 10 = 121a+11b+c
2. x = -b/2a
3. 35 = -b^2/4a + c
4. b = 4.8233-22a

There are 4 unknowns and 4 equations. After numerous attempts of trying to find a i could really use some help. The actual value of a is -0.233 or part there of. Here is my best attempt, i cant see where i went wrong.

equation 3. c = 35 + b^2/4a

10= 121a+11b+35+b^2/4a
10=121a+53.0563-242a+35+ (9.6466-212.2252+484a^2 all over 4a) You multiplied 4.8233 by 2 instead of squaring it. Should be 23.26422289.
40a = 212.2252a-484a^2+140a+9.6466-212.2252a+484a^2
40a=140a+9.6466
100a= - 9.6466
a = -0.096466
I tried finishing it out after correcting the mistake, but ended up with a = 1.488707008. There's a lot of numbers there. Could've gone wrong somewhere.

3. Originally Posted by bubbles73
Equations
1. 10 = 121a+11b+c
2. x = -b/2a
3. 35 = -b^2/4a + c
4. b = 4.8233-22a

There are 4 unknowns and 4 equations. After numerous attempts of trying to find a i could really use some help. The actual value of a is -0.233 or part there of. Here is my best attempt, i cant see where i went wrong.

..
[1.] refers to equation #1.

Here is what I did:

1. [1.] - [3.] = [13] that eliminates the variable c

2. Plug in the term for b from [4.] into the equation [13]. Calculate $\displaystyle a = -0.2326422289$

3. Plug in this value into [4.]. Calculate $\displaystyle b = 9.941429035$

4. Plug in the values of a and b into [2.]. Calculate $\displaystyle x = 21.36634669$

5. Plug in the values of a and b into [1.]. Calculate $\displaystyle c = -71.20600969$

Please check my arithmetic. I'm a master of desaster if I have to use such unusual numbers.