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Evaluate –x^2 + 2x – 4 for x = 5

Can someone review the process for this? Thank you!

Ebenezer O. | Aerospace Engr & Air Traffic Control Grad For General Ed. TutoringAerospace Engr & Air Traffic Control Gra...
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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...
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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
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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.