Question 241466
Solve using the substitution method. First, solve one equation for one variable. 
s + t = - 4,
s - t = 2
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solve the 2nd for "s":
s = t+2
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Substitute into to 1st and solve for "t":
t+2 + t = -4
2t + 2 = -4
2t = -6
t = -3
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Since s = t+2, s = -3+2 = -1
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Solution:
t = -3
s = -1
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Cheers,
Stan H.