I'm going through these tutorials for Calc III, and I came upon this slide:

Attachment 23584

source:MATH 311 - Calculus III Resources

How did the author solve for s and t?

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- April 12th 2012, 05:45 PMLexySolving the system of two equations in two unknowns
I'm going through these tutorials for Calc III, and I came upon this slide:

Attachment 23584

source:MATH 311 - Calculus III Resources

How did the author solve for s and t? - April 12th 2012, 06:55 PMskeeterRe: Solving the system of two equations in two unknowns
- April 13th 2012, 09:26 AMHallsofIvyRe: Solving the system of two equations in two unknowns
That's one good method. Another is this: the two equations are 1+ t= 2s and -2+ 3t= 3+s. Multiply the first equation by 3 to get 3+ 3t= 6s. Now subtract the second equation from that: (3+ 3t)- (-2+ 3t)= 6s- (3+ s). The "t" terms cancel giving 5= 5s- 3. Solve that for s then put that value into either of the original equations to get an equation to solve for t.