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Math·Algebra·Linear inequalities in one or two variables

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The Southern Oscillation Index (SOI) predicts weather patterns in the Pacific Ocean. SOI values less than $-7$ over a period of time predict a temporary decrease in the strength of the Pacific trade winds. Each of the following inequalities represents SOI values, $x$, over a certain period of time. Which inequality represents SOI values that predict a temporary decrease in the strength of the Pacific trade winds?

A

$-21<x<-13$

B

$-7<x<0$

C

$-7<x<7$

D

$19<x<23$