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sammy [17]
3 years ago
12

Solve using elimination. 8x − 7y = –5 –x + 4y = –15

Mathematics
2 answers:
xz_007 [3.2K]3 years ago
7 0
Steps
8x−7y=−5
Add 7y to both sides
8x−7y+7y=−5+7y
Simplify
8x=−5+7y
Divide both sides by 8
8x
8 =−
5
8 +
7y
8
Simplify
x=
−5+7y
8

ikadub [295]3 years ago
6 0

Answer:

Therefore, the values of "x" and "y" are -1000/312 and -115/39 respectively.

Step-by-step explanation:

<h3>★ Solution :-</h3>

\sf \leadsto 8x - 7y = -5 - - - (i)

\sf \leadsto -x + 4y = -15 - - - (ii)

<u>By first equation,</u>

\sf \leadsto 8x - 7y = -5

\sf \leadsto 8x = -5 + 7y

\sf \leadsto x = \dfrac{-5 + 7y}{8}

<em><u>Now, we can find the original value of y.</u></em>

\sf \leadsto -x + 4y = -15

\sf \leadsto \bigg( \dfrac{-5 + 7y}{8} \bigg) + 4y = -15

\sf \leadsto \dfrac{-5 + 7y}{8} + 4y = -15

\sf \leadsto \dfrac{-5 + 7y + 32y}{8} = -15

\sf \leadsto \dfrac{-5 + 39y}{8} = -15

\sf \leadsto -5 + 39y = -15(8)

\sf \leadsto -5 + 39y = -120

\sf \leadsto 39y = -120 + 5

\sf \leadsto 39y =  - 115

\sf \leadsto y = \dfrac{ - 115}{39}

<em><u>Now, we can find the original value of x.</u></em>

\sf \leadsto 8x - 7y = -5

\sf \leadsto 8x -7 \bigg( \dfrac{ - 115}{39} \bigg) = -5

\sf \leadsto 8x + \dfrac{805}{39} = -5

\sf \leadsto \dfrac{312x + 805}{39} = -5

\sf \leadsto 312x + 805 = -5(39)

\sf \leadsto 312x + 805 = -195

\sf \leadsto 312x = -195 - 805

\sf \leadsto 312x = -1000

\sf \leadsto x = \dfrac{-1000}{312}

\textsf {\underline{Answer-}}\\

Therefore, the values of x and y are -1000/312 and -115/39 respectively.

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