SOLUTION: I am 50 yrs old, haven't used algebra since High School and now need it and can't remember what to do to solve the following equations for B and for N:
0.63B + 0.37N = -8.4 and
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Question 334974: I am 50 yrs old, haven't used algebra since High School and now need it and can't remember what to do to solve the following equations for B and for N:
0.63B + 0.37N = -8.4 and 0.56B + 0.44N = -6.6
I know I need to pick one of the equations, determine the equation just for N, and then replace N in the other equation with that formula to solve for B. eg, for the first equation 0.37N = -8.4 - 0.63B, now I am stuck as to how to solve for B? Is it N = (-8.4 - 0.63B)/0.37? How do I perform the calculation to solve for B?
Found 4 solutions by stanbon, nerdybill, solver91311, priyaasai:
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
0.63B + 0.37N = -8.4
0.56B + 0.44N = -6.6
----------------------------
Multiply thru each equation by 100 to get rid of the decimals:
63B + 37N = -840
56B + 44N = -660
-----------------------
Multiply thru the 1st equation by 56
Multiply thru the 2nd equation by 63
-------------------------------------
56*63B + 56*37N = 56*-840
63*56B + 63*44N = 63*-660
------
Subtract the 1st equation from the 2nd and solve for "N":
700N = 5460
N = 7.8
---------------
Substitute into 56B+44N=-660 and solve for "B":
56B+44(7.8)=-660
56B = 1003
B = 17.9143
-------------------------
Cheers,
Stan H.
Answer by nerdybill(7384) (Show Source): You can put this solution on YOUR website!
0.63B + 0.37N = -8.4 (equation 1)
0.56B + 0.44N = -6.6 (equation 2)
.
Solving equation 1 for N:
0.63B + 0.37N = -8.4
0.37N = -0.63B-8.4
Divide both sides by 0.37:
N = (-0.63B-8.4)/0.37
.
Substitute the above into equation 2 and solve for B:
0.56B + 0.44N = -6.6
0.56B + 0.44(-0.63B-8.4)/0.37 = -6.6
0.56B + 1.189(-0.63B-8.4) = -6.6
0.56B - 0.75B - 9.99 = -6.6
-0.19B - 9.99 = -6.6
-0.19B = 3.39
B = -17.84
.
Substitute the above into equation 1 and solve for N:
0.63B + 0.37N = -8.4
0.63(-17.84) + 0.37N = -8.4
0.63(-17.84) + 0.37N = -8.4
-11.24 + 0.37N = -8.4
0.37N = 2.84
N = 7.68
Answer by solver91311(24713) (Show Source): You can put this solution on YOUR website!
Your first step was correct.
Now take the right hand side mess and replace N in the second equation.
\ =\ -6.4)
Now you have an equation, albeit an extremely ugly one, in one variable that can be solved by ordinary algebraic means. Once you have a value for 
, you can substitute that value back into either of the original equations to produce a single-variable equation in 
.
This is mostly just nasty arithmetic. Enjoy.
John
My calculator said it, I believe it, that settles it
Answer by priyaasai(1) (Show Source): You can put this solution on YOUR website!
16b^3
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