3 years ago

Multiple choice questions will mark brainlist answer asap

Mathematics

1 answer:

Vesna [10]3 years ago

3 0

11, -8, and 7 are the answers...

Please mark as brainliest... I really need it...

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Which of the following equations shows how substitution can be used to solve

maxonik [38]

Answer: Choice B)

2x+5(2x+3) = 3

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Reasoning:

We start with the second equation 2x+5y = 3

Since y = 2x+3 from the first equation, we can replace every copy of y with (2x+3). This replacement is valid because y and 2x+3 are the same.

So that's how we go from 2x+5y = 3 to 2x+5(2x+3) = 3

This replacement is done to get rid of the y variable, and it allows us to solve for x later on.

3 0

3 years ago

Solve the system of linear equations by elimination 2x+7y=1 2x-4y=12

pishuonlain [190]

$\left\{\begin{array}{ccc}2x+7y=1\\2x-4y=12&\text{change the signs}\end{array}\right\\\\\underline{+\left\{\begin{array}{ccc}2x+7y=1\\-2x+4y=-12\end{array}\right}\qquad\text{add both sides of equations}\\.\qquad\qquad11y=-11\qquad\text{divide both sides by 11}\\.\qquad\qquad \boxed{y=-1}\\\\\text{Put the value of y to the first equation:}\\\\2x+7(-1)=1\\2x-7=1\qquad\text{add 7 to both sides}\\2x=8\qquad\text{divide both sides by 2}\\\boxed{x=4}\\\\Answer:\ \boxed{x=4\ and\ y=-1\to(4,\ -1)}$