staciereibly
3 Answers
chelleanne
r = records
t = tapes
Two equations:
2r + 3t = $31.00
3r + 2t = $29.00
Eliminate one of the variables and solve for the other.
3(2r + 3t = $31.00)
-2(3r + 2t = $29.00)
6r + 9t = $93.00
-6r - 4t = -$58.00
5t = $35.00
5t/5 = $35.00/5
t = $7.00
Now, solve for r. Put the value of t in either equation.
2r + 3($7.00) = $31.00
2r + $21.00 = $31.00
2r + $21.00 - $21.00 = $31.00 - $21.00
2r = $10.00
2r/2 = $10.00/2
r = $5.00
| 9 years ago. Rating: 3 | |
Look below!
r = records
t = tapes
2r + 3t = $31.00
3r + 2t = $29.00
coefficient variables answer column
matrix's
determinant
r t
2 3 r $31
3 2 t $29
D = (2)(2) - (3)(3) = 4 - 9 = -5
D(r)
$31 3
$29 2
($31)(2) - ($29)(3) = $62 - $87 = $-25/-5 = $5
r = $5
D(t)
2 $31
3 $29
(2)($29) - (3)($31) = $58 - $93 = $-35/-5 = $7
t = $7
Bob/PKB
2R + 3T = $31.00
3R + 2T = $29.00 I notice that buying one more record and one less tape results in $2 less cost. That tells me that a record is $2 less than a tape.
I'm going to use the 3R + 2T= $29 and substitute 2 more records for the two tapes. I'll have 5 records and no tapes. Since I am spending $2 less for each record instead of tape, I'll be saving $4 more, so I'll subtract that from the $29.00
5R = $25.00 Obviously, a record costs $5 (25/5). A tape is $2 more, which is $7.
It's nice to have the answer provided, but knowing how to get the answer helps. This is not the right way to get it algebraically. But it's logical and you can explain it if you have to do so.
| 12 years ago. Rating: 1 | |
pioneer2
