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3 years ago

When solving this system by elimination, which variable is the most convenient to eliminate,

Mathematics

1 answer:

kobusy [5.1K]3 years ago

4 0

Answer:

Y is the appropriate variable and the most easiest and convenient to eliminate

name 2x + y = 7 as equation i

and 3/2 x - y = 7/2 as equation ii

then add equation i and ii together

(3/2 + 2) x + y - y = (7 + 7/2)

(7/2) x = (21/2)

x = 3

then put in x = 3 in equation i

4 + y = 7

x = 7 - 4

x = 3

Therefore x = 3 and y = 3

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Answer:

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P.Q. = $\frac{\bar X - \mu}{\frac{s}{\sqrt{n} } }$ ~ $t_n_-_1$

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P( $-2.878 \times {\frac{s}{\sqrt{n} } }$ < ${\bar X - \mu}$ < $2.878 \times {\frac{s}{\sqrt{n} } }$ ) = 0.99

P( $\bar X -2.878 \times {\frac{s}{\sqrt{n} }$ < $\mu$ < $\bar X +2.878 \times {\frac{s}{\sqrt{n} }$ ) = 0.99

99% confidence interval for $\mu$ = [ $\bar X -2.878 \times {\frac{s}{\sqrt{n} }$ , $\bar X +2.878 \times {\frac{s}{\sqrt{n} }$ ]

= [ $22.4 -2.878 \times {\frac{3.8}{\sqrt{19} }$ , $22.4 +2.878 \times {\frac{3.8}{\sqrt{19} }$ ]

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