Question

The work of a student to solve a set of equations is shown:

Equation A: y = 15 − 2z
Equation B: 3y = 3 − 4z
Step 1: −3(y) = −3(15 − 2z) [Equation A is multiplied by −3.]
3y = 3 − 4z [Equation B]
Step 2: −3y = 15 − 2z [Equation A in Step 1 is simplified.]
3y = 3 − 4z [Equation B]
Step 3: 0 = 18 − 6z [Equations in Step 2 are added.]
Step 4: 6z = 18
Step 5: z = 3
In which step did the student first make an error?

Answer 1

what do you tthink?

Answer 2

im thnking step 2

Answer 3

yes it would be do you know why

Answer 4

know not realy.

Answer 5

no*

Answer 6

So in step one −3(y) = −3(15 − 2z) You wwould multiply whats on the outside of the parethises with whats on the inside do you know how to do that

Answer 7

You need to multiply BOTH sides to keep the equation balanced, right?

Answer 8

ok so -3*15, and -3*2 correct?

Answer 9

Yes exactly

Answer 10

so you would have -3y = -45 + 6

Answer 11

so that would make step two incorrect

Answer 12

6z

Answer 13

ohh, ok i see it know

Answer 14

yes 6z sorry @skullpatrol

Answer 15

good :) @WILD1

Answer 16

@skullpatrol and @Hannah_Waller thank yall both. medal and fan for hannah and skullpatrol. @Hannah_Waller can you give skullpatrol a medal for me?

Answer 17

i did :)

Answer 18

thank you:)

Answer 19

Thanks for asking questions :)

Answer 20

no problem. thanks for helping and solving:)