Несколько раз подносим до квадрата
1) 17+√(√х-6)=25
√(√х-6)=8
2) √х-6=64
√х=70
х=4900
Ответ: 4900
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(b/a-b-b/a+b)*a-b/b=b*(a+b)-b*(a-b)/(a-b)*(a+b)*a-b/b=ab+b²-ab+b²/a+b*1/b=2b²/a+b*1/b=2b/a+b
<span>a2 – b2 = (a + b)(a – b),</span>
<span>(a + b)2 = a2 + 2ab + b2,</span>
<span>(a – b)2 = a2 – 2ab + b2,</span>
<span>a3 + b3 = (a + b)(a2 – ab + b2),</span>
<span>a3 – b3 = (a – b)(a2 + ab + b2),</span>
<span><span>an – bn = (a – b)(a<span>n – 1</span> + a<span>n – 2</span>b + a<span>n – 3</span>b2 + … + ab<span>n – 2</span> + b<span>n – 1</span>)</span>,</span>
<span>(a + b)3 = a3 + 3a2b + 3ab2 + b3 = a3 + b3 + 3ab(a + b),</span>
<span>(a – b)3 = a3 – 3a2b + 3ab2 – b3 = a3 – b3 – 3ab(a – b).
</span>
S=
S=2×(-6)+3(10-1)10÷2=(-12+27)×5=15×5=75