1. 5¹⁰ +5⁸ -5⁹ =5⁸(5² +1 -5) = 5⁸*21 =5⁷*5*21 =5⁷*105 || делится на 105|| .
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2. √(1 24/25 ) -√(0,09)*√81 +√(3² +4²)*√(0,0625) =√(49/25) -√(9/100) *√9² +√5² *√(0,25)² =7/5 -9/10*9 +5*0,25 =
1,4 -8,1+1,25 = -5,45.
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3. a =13q₁ +8 ; b=13q₂ +10 .
a*b = (13q₁ +8)(13*q₂ +10) = 13² q₁q₂ +13*10q₁ + 13*8q₂+ 80 =.
13² q₁q₂ +13*10q₁ + 13*8q₂+ 13*6 + 2 =13(13 q₁q₂ +10q₁ + 8q₂+ 6) +2 . || r =2||.
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4.√((7-4√3)/(5-2√6)) -√((6-4√2)/(5+2√6)) -4√2 =√((2²-2*2√3 +(√3)²)/(3-2√3*√2 +2)) -√((4-2*2*√2 +2)/(3+2√3*√2 +2) ) - 4√2 = √((2-√3)²)/(√3-√2)² ) -√((2-√2)²/(√3+√2)²) - 4√2 = (2-√3)/(√3-√2) -(2-√2)/(√3+√2) - 4√2 = (2-√3)(√3+√2) -(2-√2)(√3-√2) - 4√2 =
2√3+2√2 -3 -√3*√2 -2√3 +2√2 +√3*√2 -2 - 4√2 = - 5.
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5. (x² +x√2)/(x² +2) *( x/(x-√2) -√(2) / (x+√2) ) =
(x² +x√2)/(x² +2) *(x(x+√2) -√(2) * (x-√2) ) / (x+√2) (x-√2) )=
(x² +x√2)/(x² +2) *(x²+x√2 -x√2 +2 ) / (x² -2) )=
(x² +x√2)/(x² +2) *(x² +2 ) / (x² -2) ) = x(x+√2) / (x +√2)(x -√2) =x /(x -√2) .
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6. ( √(19 +8√3) +√(7-4√3) ) *x√y /(√x²y³ +√x³y²) =
( √(4+√3)² +√(2 -√3)² ) *x√y /xy(√y +√x) =( 4+√3 +2 -√3 ) *1 / √y(√y +√x ) =
6/√y (√y +√x )= || x =121 , y =16 || = 6/(√16(√16 +√121 )) =6/(4(4+11)) =
=6/(4*15) =6/60 = 0,1.