SOLUTION: 1. It takes Bill 6 hours longer than John to plow a certain field. Together they can plow it in 4 hours. How long would it take each man alone to plow the field? 2. Using a grap

Question 389334: 1. It takes Bill 6 hours longer than John to plow a certain field. Together they can plow it in 4 hours. How long would it take each man alone to plow the field?
2. Using a graphing calculator find the roots of the equation to the nearest hundredth:
x^7+x^5-2x^3+3x^2-1=0
Found 3 solutions by haileytucki, richard1234, Finavon:
Answer by haileytucki(390)   (Show Source): You can put this solution on YOUR website!

x+y=4_x=y+6
Since y does not contain the variable to solve for, move it to the right-hand side of the equation by subtracting y from both sides.
x=-y+4_x=y+6
Replace all occurrences of x with the solution found by solving the last equation for x. In this case, the value substituted is -y+4.
x=-y+4_(-y+4)=y+6
Remove the parentheses around the expression -y+4.
x=-y+4_-y+4=y+6
Since y contains the variable to solve for, move it to the left-hand side of the equation by subtracting y from both sides.
x=-y+4_-y+4-y=6
Since -y and -y are like terms, subtract y from -y to get -2y.
x=-y+4_-2y+4=6
Since 4 does not contain the variable to solve for, move it to the right-hand side of the equation by subtracting 4 from both sides.
x=-y+4_-2y=-4+6
Add 6 to -4 to get 2.
x=-y+4_-2y=2
Divide each term in the equation by -2.
x=-y+4_-(2y)/(-2)=(2)/(-2)
Simplify the left-hand side of the equation by canceling the common factors.
x=-y+4_y=(2)/(-2)
Simplify the right-hand side of the equation by simplifying each term.
x=-y+4_y=-1
Replace all occurrences of y with the solution found by solving the last equation for y. In this case, the value substituted is -1.
x=-(-1)+4_y=-1
Multiply -1 by each term inside the parentheses.
x=1+4_y=-1
Add 4 to 1 to get 5.
x=5_y=-1
This is the solution to the system of equations.
x=5_y=-1
It would take John 5 hours to plow the field, and Bill (5+6 hours) 11 hours to plow the field.
Answer by richard1234(7193)   (Show Source): You can put this solution on YOUR website!
For the second problem, use nsolve(...) or solve(...) to find a root. After that, I think you can find the other roots by multiplying by the complex number .
Answer by Finavon(81)   (Show Source): You can put this solution on YOUR website!
John t hrs
Bill (t+6) hrs
Together 4 hrs
Each contribute to this whole

Multiply each side by t and by t+6
4(t+6) + 4t = t(t+6)
4t + 24 + 4t = t^2 + 6t
Rearrange

Solves as (t+4)(t-6) with t=6 as only real solution
John takes 6 hrs; Bill takes 12 hrs
Check:

2. Using a graphing calculator find the roots of the equation to the nearest hundredth:
x^7+x^5-2x^3+3x^2-1=0
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