1)
I:y=3x-4
II:9x-3y=14
substitute y into II:
9x-3*(3x-4)=14
9x-9x+12=14
12=14
this is obviously not equal so there is no solution, the lines are parallel
2)
I:y=4x+6
II:5x-y=6
substitute y into II:
5x-(4x+6)=6
5x-4x-6=6
x=12
substiute x into II:
5*12-y=6
-y=6-60
-y=-54
y=54
the solution is (12,54)
Answer is x=-7 x=6 or choice A
A) 4a - 3b + 2c
4(2, -1, 5) - 3(4, 3 , -2) + 2(5, 4, 0) = (8, -4, 20) - (12, 9, - 6) + (10, 8, 0) =
= (8 - 12 + 10 , -4 - 9 + 8 , 20 + 6 + 0) = (6, - 5, 26)
Answer: (6, - 5, 26)
b) magnitude of vector b

c) vector of length 7 parallel to vector c
=> m(5,4,0) = (5m,4m,0)
=>

=> m = 7 / √41 ≈ 1.093
=> 1.093 (5, 4, 0) = (5.465 , 4.372, 0)
Answer: (5.465 , 4.372 , 0)
Original price:
6(3.5)
21
New Price:
1.15(21)
24.15
24.15-21
$3.15 more