Question

решите плиз
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Answer 1

1)

$displaystyle x^2-4=0\\x^2=4\\x= pm2$

2)

$displaystyle 9x^2=0\\ x^2=0\\ x=0$

3)

$displaystyle 5frac{2}{3}x^2=0\\x^2=0\\x=0$

4)

$displaystyle -1.4x^2-68.6=0\\-1.4x^2=68.6\\x^2=68.6/(-1.4)\\x^2= -49$

решений нет

5)

$displaystyle frac{3}{11}x^2-33=0\\frac{3}{11}x^2=33\\x^2=33:frac{3}{11}\\x^2=121\\x= pm 11$

6)

$displaystyle 14x^2+140x=0\\14x(x+10)=0\\x=0; (x+10)=0\\x=0; x=-10$

7)

$displaystyle -0.08x^2-8x=0\\-8x(0.01x+1)=0\\x=0; 0.01x+1=0\\x=0; x=-100$

8)

$displaystyle frac{1}{78}x^2-18.5x=0\\x(frac{1}{78}x-18.5)=0\\x=0; frac{1}{78}x=18.5 \\x=0; x=1443$