Х+7_х^2-25 - 2 х+2_х^2-25 при х=-5,1

X+7/x²-25-2x+2/x²-25

x+7-2x (x²-25) + 2/x²-25

x+7-2x³+50x+2/x²-25

-2x³+51x+9/x²-25

-2 * (-5.1) ³+51 * (-5.1) + 9 / (-5.1) ²-25

-2 * (-5.1) ³-206,1+9 / (-51/10) ²-25

2 * (51/10) ³-2601/10+9/51²/100-25

2*51³/10³-2601/10+9/51²-2500/100

2*51³/5³*2³-2601/10+900/51²-2500

51³/5³*2²-2601/10+900/2601-2500

51³/125*4-2601/10+900/101

51³/500-2601/10+900/101

51³/500-253701/1010

≈14.11