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4.Does (3,-5) lie on the line y = -2x +1? Why or why not?5. Evaluate -y^2 – 2xy when x =-5 and y = 3.Can I get help with 4 and 5?

User Anthony Corbelli
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1 Answer

22 votes
22 votes

Question 4:

The equation of the line:


y\text{ = -2x+1}

If the point (3, -5) lies on the line, when we substitute the x-value into the equation, we should have the given y-value.

Hence,


\begin{gathered} x\text{ = 3} \\ \text{Substitutitng:} \\ y=\text{ -2(3) + 1} \\ =\text{ -6 + 1} \\ =\text{ -5} \end{gathered}

We can conclude that the point (3, -5) lies on the line.

Question 5

Given expression:


=-y^2-2xy

Where:

x = -5 and y = 3:

Substituting we have:


\begin{gathered} =-3^2\text{ -2(-5)(3)} \\ =\text{ -9 +30} \\ =\text{ 21} \end{gathered}

Answer: 21

User Tony Bourdeaux
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