Answer:
He made a mistake in his calculations when simplifying 5x - 2y
Step-by-step explanation:
Given
The coordinate pair
[tex](x,y) = (2,-2)[/tex]
The equations
[tex]7x + 9y = ?[/tex]
[tex]5x - 2y = ?[/tex]
Dimitri's Solution
[tex]Equation\ 1: 7x + 9y = -4.[/tex]
[tex]7(2) + 9 (-2) = -4.[/tex]
[tex]14 + (-18) = -4.[/tex]
[tex]-4 = -4.[/tex]
[tex]Equation\ 2: 5x -2y = 6.[/tex]
[tex]5(2) - 2 (-2) = 6.[/tex]
[tex]10 - 4 = 6.[/tex]
[tex]6 = 6.[/tex]
Required
Identify Dimitri’s mistake
In the first equation, Dimitri made no mistake.
However, he made a mistake when simplifying the second equation.
We have:
[tex]5x - 2y[/tex]
and
[tex](x,y) = (2,-2)[/tex]
Substitute [tex]x = 2[/tex] and [tex]y = -2[/tex]
So, we have:
[tex]5(2) -2(-2)[/tex]
Open bracket
[tex]10 +4[/tex]
Finally, we have:
[tex]14[/tex]
