№2
в)x^2 +64=0
x^2 = - 64
/x/=√64
x= 8 x= - 8
Ответ: 8 ; - 8.
г) 3x^2 - 15=0
3x^2 = 15
x^2 = 5
/x/ = √5
x=√5 x= - √5
Ответ: √5 ; -√5
№3
x^2-3x-10=0
D=b^2 - 4ac = ( -3)^2 - 4 * 1 * ( - 10) = 9+40=49
√D=7
x1=3+7 / 2 = 5
x2= 3 - 7 / 2 = ⇒ - 2 - Является .
Ответ: 5; - 2
№4
![( \sqrt{5}- \sqrt{2})^2=( \sqrt{6})^2-2 \sqrt{5}* \sqrt{2}+( \sqrt{2})^2=5- 2\sqrt{10}+2=7+2 \sqrt{10}](https://tex.z-dn.net/?f=%28+%5Csqrt%7B5%7D-+%5Csqrt%7B2%7D%29%5E2%3D%28+%5Csqrt%7B6%7D%29%5E2-2+%5Csqrt%7B5%7D%2A+%5Csqrt%7B2%7D%2B%28+%5Csqrt%7B2%7D%29%5E2%3D5-+2%5Csqrt%7B10%7D%2B2%3D7%2B2+%5Csqrt%7B10%7D+)
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![(4- \sqrt{10})(4+ \sqrt{10})=(4^2-( \sqrt{10})^2)=16-10=6](https://tex.z-dn.net/?f=%284-+%5Csqrt%7B10%7D%29%284%2B+%5Csqrt%7B10%7D%29%3D%284%5E2-%28+%5Csqrt%7B10%7D%29%5E2%29%3D16-10%3D6)
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Решение во вложении-------------------
Ответ: 18,9*t^2+27*t+31,5*t+45=
=18,9*t^2+58,8*t+45.
Объяснение:
40m + 3n = 13
20m - 7n = - 5
Решение
- 40m + 14n = 10
17n = 23
n = 23/17 = 1 6/17
20m - 7•( 23/17 ) = - 5
20m = - 5 + ( 161/17 )
20m = - 5 + 9 8/17
20m = 4 8/17
m = 76/17 : 20
m = 38/170