Algebra · real student question

Simplify x^2 + 3^2 + 1.

Question

Simplify

x2+32+1x^{2}+3^{2}+1

Step-by-step solution

  1. Evaluate the numeric power before touching anything else. Order of operations puts exponents ahead of addition, and 323^{2} involves no variable at all, so it is simply a number:

    32=3×3=93^{2}=3\times3=9

    A frequent error is reading 323^{2} as 3×2=63\times2=6; the exponent counts how many copies are multiplied, not a factor.

  2. Rewrite the expression with that value in place.

    x2+32+1=x2+9+1x^{2}+3^{2}+1=x^{2}+9+1

  3. Combine only the constants. 99 and 11 are like terms (both pure numbers), so they add. The term x2x^{2} is not like them — it carries a variable — so it cannot join in:

    9+1=10x2+109+1=10\qquad\Longrightarrow\qquad x^{2}+10

    In particular x2+9x^{2}+9 does not become x2+9x^{2+9} or 9x29x^{2}; addition never merges a variable term with a constant.

  4. Check at two values. At x=2x=2: original 4+9+1=144+9+1=14, simplified 4+10=144+10=14 ✓. At x=5x=-5: 25+9+1=3525+9+1=35 and 25+10=3525+10=35 ✓. Agreement holds at every integer from 20-20 to 1919 ✓.

  5. Note what the form tells you. x2+10x^{2}+10 is a parabola shifted up 1010 units, so its minimum value is 1010 at x=0x=0 and it is never zerox2+10=0x^{2}+10=0 would need x2=10x^{2}=-10, impossible for real xx. That also means x2+32+1>0x^{2}+3^{2}+1>0 for every real xx.

Answer

x2+10x^{2}+10

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