Question

ANSWER NOWWWWWWWWWWWW!100POINTS!!Using the linear combination method, what is the solution to the system of linear equations 7 x minus 2 y = negative 20 and 9 x + 4 y = negative 6?

Answer 1

Answer:

7x - 2y = -20 _____(1)

9x + 4y = -6 ________(2)

Multiplying equation (1) by (2)

We get ,

14x - 4y = - 40 _____(3)

Therefore, on adding equations (1) and (3)

23x = -34

X = -34/23

putting the value of x = -34/23 in equation (1) we get,

➡️ 7(-34/23) - 2y = - 20

➡️ - 30.34 = 2y

➡️ y = -15.17

therefore, { x = -34/23 and y = -15.17 } ans.

Step-by-step explanation:

Answer 2

Aɴꜱᴡᴇʀ

$\huge \sf{x = - 2} \\ \huge \sf{}y = 3$

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Gɪᴠᴇɴ

$\sf{7x - 2y = - 20 - - - - - 1} \\ \sf{9x + 4y = - 6 - - - - - - 2}$

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Tᴏ ꜰɪɴᴅ

The value of 'X' and 'Y'

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Fᴏʀᴍᴜʟᴀ Uꜱᴇᴅ

Substitution method

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Sᴛᴇᴘꜱ

$\sf{we \: can \: change \: 1 \: into \: x = \frac{ - 20 + 2y}{7} } \\ \sf{substituting \: this in \: 2 \: we \: get \: } \\ \sf{9( \frac{ - 20 + 2y}{7}) + 4y = - 6 } \\ \sf{ = ( - 180 )+ 18y + 28y = - 6 \times 7} \\ \sf{ = 46y = - 42 + 180} \\ \sf{y = \frac{138}{46} } \\ \sf{}which \: gives \: y = 3$

$\\ \sf{so \: substituting \: the \: value \: of \: y \: in \: the \: equation \: formed \: by \: us \: first}$

$\sf{we \: get \: x = \frac{ - 20 + 2(3)}{7} } \\ \sf{ x = \frac{ - 14}{7} } \\ \sf{x = - 2}$

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$\huge{\mathfrak{\purple{hope\; it \;helps}}}$