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Marta tried solve the system below, but she made a mistake. Read carefully and try to figure out what her mistake was.

Question

jadadunn · Answer

yes

Vocaloid · Answer

can you post the full question please?

jadadunn · Answer

Marta tried solve the system below, but she made a mistake. Read carefully and try to figure out what her mistake was.

solve the system below:
10x+y=22
2x+y=-2

y=22-10x=10x+(22-10x)=22
10x+22-10x=22
0x+22=22
22=22
infinitely many solutions.

Explain the mistake.

Vocaloid · Answer

she solved for y in equation 1 but substituted it again into equation 1 which is meaningless

she has to substitute y = (22-10x) into equation 2 to get the real answer

^ that is her mistake

jadadunn · Answer

thank you