Mathematics: Serena wants to solve the following system of equations in the most efficient way. 2 x + 3 y = 18. x + 7 y = 31. She plans to solve for x in the first equation as her first step since both 2 and 3 can be divided into 18. Why is Serina mistaken? Serina should have solved for x in the second equation because it has a coefficient of 1. Serina should have solved for y in the first equation because dividing by 3 instead of by 2 would give a smaller number in the solution. Serina should have solved for

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Serena wants to solve the following system of equations

kat9490

19.01.2022

Serina should have solved for x in the second equation because it has a coefficient of 1.

Step-by-step explanation:

we have

2x+3y=18 ----> equation A

x+7y=31 ---> equation B

we know that

To solve the system of equations in the most efficient way, solve for x equation B and then substitute the value of x in equation A

x=31-7y ----> equation C

substitute equation C in equation A

2(31-7y)+3y=18

solve for y

$62-14y+3y=18\\11y=62-18\\11y=44\\y=4$

Find the value of x

substitute the value of y in the equation C

x=31-7(4)=3

The solution is (3,4)

therefore

Serina should have solved for x in the second equation because it has a coefficient of 1.

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