How do you solve these for s and t using the following equations?: $3 s - 5 t = - 30$ $3s-5t=-30$ and $7 s + 11 t = 32$ $7s+11t=32$

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Answer 1 · 2015-10-21T04:00:44

$s = - 2.5$ $s=-2.5$ $t = 4.5$ $t=4.5$

You first need to find the equation in terms of either $s$ $s$ or $t$ $t$ . I'm gonna do it in $s$ $s$ .

So
= $3 s - 5 t = - 30$ $3s-5t=-30$
= $3 s = - 30 + 5 t$ $3s=-30+5t$
= $s = \frac{- 30 + 5 t}{3}$ $s=(-30+5t)/3$ ------ (1)

$7 s + 11 t = 32$ $7s+11t=32$
$7 s = 32 - 11 t$ $7s=32-11t$
$s = \frac{32 - 11 t}{7}$ $s=(32-11t)/7$ ------ (2)

Now equate the 2 terms of $s$ $s$

= $\frac{- 30 + 5 t}{3} = \frac{32 - 11 t}{7}$ $(-30+5t)/3=(32-11t)/7$

= $7 (- 30 + 5 t) = 3 (32 - 11 t)$ $7(-30+5t)=3(32-11t)$

= $- 210 + 35 t = 96 - 33 t$ $-210+35t=96-33t$

= $- 210 - 96 = - 35 t - 33 t$ $-210-96=-35t-33t$

= $- 306 = - 68 t$ $-306=-68t$

= $t = \frac{- 306}{- 68}$ $t=(-306)/-68$

= $t = 4.5$ $t=4.5$

Now swap the value of t in an original equation,

$s = \frac{- 30 + 5 (4.5)}{3}$ $s=(-30+5(4.5))/3$

$s = - \frac{7.5}{3}$ $s=-7.5/3$

Therefore,

$s = - 2.5$ $s=-2.5$ $t = 4.5$ $t=4.5$

How do you solve these for s and t using the following equations?: 3s−5t=−303s-5t=-30 and 7s+11t=327s+11t=32