3 years ago

How do I find the mistake the student did?

Mathematics

1 answer:

Maslowich3 years ago

4 0

Answer:

Step-by-step explanation:

What he did at the end of the given equations is solve for x in x + 8y= 21

x = 21 - 8y Substitute that result in the top equation.

7(21 - 8y) + 5y = 14 is the correct step To continue Remove the brackets

147 - 56y + 5y = 14 Combine

147 - 51y = 14 Add 51y to both sides.

147 = 51y + 14 Subtract 14 from both sides.

133 = 51y divide by 51

y = 2.61 rounded.

The incorrect step is underlined and italicized.

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