Question

Which is the first error that Tomas made? Tomas substituted the 3 for x when he should have substituted 6 for x. Tomas added 6 to both sides of the equation instead of subtracting 6. Tomas should have written the equation as . Tomas substituted 3 for x when he should have substituted 3 for y.

Answer 1

Tomas added 6 to both sides of the equation instead of subtracting 6

Explanation:

Find the complete question in the comment section.

Given the equation 2x+6y=12 to represent the total cost, where x represents the number of pounds of granola and y represents the number of pounds of walnuts.

If he buys 3pounds of granola, and he need to get amount of walnut, he should have substituted x = 3 into the expression to get y as shown:

`2x+6y=12\\2(3)+6y=12\\6+6y = 12\\subtract\ 6 \ from \ both \ sides \\6+6y-6 = 12-6\\6y = 6\\y = (6)/(6)\\ y = 1`

Comparing the calculation with Tomas's, we can see that Tomas added 6 to both sides of the equation on line 3 instead of subtracting 6 from both sides of the equation. This was Tomas first error.