Solve systems by substitution method x + y = 12 3x - y = 20

Mathematics

1 answer:

labwork [276]3 years ago

3 0

Step-by-step explanation:

x+y=12

3×+y=20

×=12-y

3 (12-y)+y=20

36-3y+y=20

36-4y=20

-4y=20-36

-4y= -16

y =16÷4

y=4

×+y=12

×+4=12

×=12-4

×=8

therefoer;y=4,x=8

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Answer:

a. $4\ pencils$

b. His teacher will receive more pencils (See explanation).

Step-by-step explanation:

a. The total number of pencils Louis brings to school is:

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Then, in order to calculate the number of pencils Louis’s teacher will receive after he gives each of his 15 classmates an equal number of pencils, you need to solve the division show in the picture attached.

Notice that the remainder obtained is: $4$ .

This means that Louis’s teacher will receive 4 pencils.

b. If Louis decides instead to take an equal share of the pencils along with his classmates, his teacher will receive more pencils; because the amount of pencils each classmate will receive will be less. This means that the number of pencils leftover will increase, leaving more pencils for his teacher.