Помогите решить уравнение 90x+x-14*120=2100 и x-20=260-x*4

Question

Помогите решить уравнение 90x+x-14*120=2100 и x-20=260-x*4

Answer 1

90x+x-14*120=2100
90x^2-1680=2100
90x^2=2100+1680
90x^2=3780
x^2=42

Comments

x-20=260-x*4

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x-20=260-4x

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4x+x=260-4x

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4x+x=260+20

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5x=280

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x=56