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OpenStudy (abbycross167):
8-18-8?
OpenStudy (vhtran):
8--18-8, Don'y forget the negative on the 18 :P
OpenStudy (vhtran):
What happens when you have 2 negatives?
OpenStudy (abbycross167):
positive right?
OpenStudy (vhtran):
yes :D so 8+18-8
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OpenStudy (abbycross167):
= 18
OpenStudy (mathstudent55):
You need to be careful when you square a negative number.
\(-3^2 \ne (-3)^2\)
\(-3^2 = -9\)
\((-3)^2 = 9\)
Also, make sure you substitute the correct numbers in for the variables.
\(\color{red}{x = 2}\), and \(\color{green}{y = -3}\).
\( 2\color{red}{x}^2 - 3\color{red}{x}\color{green}{y} – 2\color{green}{y}^2 \)
\(= 2(\color{red}{2})^2 - 3(\color{red}{2})(\color{green}{-3}) - 2(\color{green}{-3})^2\)
\(=2(4) - (-18) - 2(9)\)
\(= 8 + 18 - 18\)
\(= 8\)
OpenStudy (mathstudent55):
The correct answer is 8, not 18.
OpenStudy (mathstudent55):
Do you understand the steps?
OpenStudy (abbycross167):
Yes sir/ma'am, thank you very very much!!
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