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)

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

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)

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