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Evaluate –x^2 + 2x – 4 for x = 5

Can someone review the process for this? Thank you!
 

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Ebenezer O. | Aerospace Engr & Air Traffic Control Grad For General Ed. TutoringAerospace Engr & Air Traffic Control Gra...
4.6 4.6 (13 lesson ratings) (13)
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-x2 + 2x - 4.......................where x = 5
 
substitute x into the equation.
 
-(5)2 + 2(5) - 4
 
= -25 + 10 - 4
 
= -19
Shelly J. | Excellent Maths Tutoring for academic successExcellent Maths Tutoring for academic su...
5.0 5.0 (229 lesson ratings) (229)
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Hi Abby,
 
For x=5,
 
-x²+2x-4   = -(5)²+2(5)-4
 
                =-25+10-4
 
                =-15-4
 
                =-19
David T. | Experienced Math and Physics TutorExperienced Math and Physics Tutor
4.8 4.8 (12 lesson ratings) (12)
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The evaluation of this expression is in the proper reading of the notation:
 
–x^2 + 2x – 4
 
is the same as:
 
= –(x)^2 + 2(x) – 4
 
the parentheses are implicit, but inform the evaluator. This is then rewritten more clearly as:
 
= –(x * x) + 2(x) – 4
 
which then evaluates under x = 5 by:
 
= –(5 * 5) + 2 * 5 – 4
 
where " * " is multiplication. The rest is computation is straightforward, with proper use of order of operations.