Let r = (t,t^2,t^3)
Then r' = (1, 2t, 3t^2)
General Line integral is:

The limits are 0 to 1
f(r) = 2x + 9z = 2t +9t^3
|r'| is magnitude of derivative vector


Fortunately, this simplifies nicely with a 'u' substitution.
Let u = 1+4t^2 +9t^4
du = 8t + 36t^3 dt

After integrating using power rule, replace 'u' with function for 't' and evaluate limits:
Answer:
5
Step-by-step explanation:
K equals 3 and so 15/3 equals 5.
.......................................
Answer:
x= 8
Step-by-step explanation:
103 - 4x = 71
You have to isolate -4x by using the subtraction property of equality on 103
103(-103) -4x = 71(-103)
-4x = -32
Use Multiplication Property of Equality for the negative
4x = 32
Divide 4 from both sides
x= 8
X = y + 3
2x + y = 9
Solution..
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Substitute for x=y+3 in the second equation...
2x+y = 9
2(y+3)+y=9
2y+6+y=9
3y+6=9
3y=9-6
3y=3
y=3/3
y=1....
Substitute for y=1 in the first equation...
x=y+3
x = 1+3
x=4..
Am sure the answer is quite evident now...