I have a similar problem to <3Medic+Droid<3's one about corn dogs and burritos for his(or hers) Algebra Answer Check thingy. So i've been trying to figure that one out so i might better understand how to do mine-but i keep getting stuck on this part of the substitution.(well i think this is where my mistake is.)

Question

c=-b+600
.35(-b+600)+.75b=360 <---this part

When i distribute out .35 i get
-.35b+210+.75b=360
Kay, so then after i combine like terms(i chose to move the .75b) subtract 210 from both sides and all that good stuff, i get
-1.1b=150 <--i also think this is wrong
b=-136.3636364 (rounded to -136.36)
When i plug it into c=-b+600, i get that c=463.64.
I know this is wrong, but i don't know what i did to get this answer. Can you help me out please? Thank you.

Answer 1

Ok, the signs are different on the left side b's.

.40b=150 then solve for b.

Answer 2

-.35b+210+.75b=360 agree
then
.40 b + 210 = 360
.40 b = 150
b = 375

Answer 3

Oh thank you,Thank You, THANK YOU!

Answer 4

kay, so how would you turn that into a matrix in the form of
[1 0 A]
[0 1 B] ?
Would you just plug c in for A and b in for..well B? if not then how do you solve this?

Answer 5

Kat

.4 b + 0 c = 150
1 b + 1 c = 600

augmented matrix:

0.4 0.0 150
1.0 1.0 600

divide top equation by .4 to get 1 in upper left

1.0 0.0 375
1.0 1.0 600

subtract second row from first to make new second row with 0 on left
1.0 0.0 375
0.0 -1.0 -225
divide row two by -1 to get identity matrix augmented with solution
1.0 0.0 375
0.0 1.0 225
so
b = 375
c = 225

Answer 6

thx