Peter solved this equation
6 x y = 490 - 4
6 x y = 486
y = 492
Explain his mistake.
He removed the 6 from the 6 times y side and added 6 to the 486 on the other side. He should have divided both sides by 6.
To understand Peter's mistake, let's analyze the given equation:
6xy = 490 - 4
6xy = 486
The goal is to solve for the value of y.
First, Peter correctly subtracted 4 from 490, obtaining 486:
6xy = 486
However, his mistake lies in the following step. To isolate y, Peter should have divided both sides of the equation by 6, like this:
(6xy) / 6 = 486 / 6
xy = 81
Now, to find the value of y, we need to divide both sides of the equation by x:
(xy) / x = 81 / x
y = 81 / x
Therefore, the correct expression for y is y = 81 / x.
In Peter's solution, he skipped the step of dividing by 6, which led him to the incorrect expression y = 492.