Решите уравнение 7x²+21x=0 Упростите выражение 3m(2m-1)-(m+3)(m-2)

Question

Решите уравнение 7x²+21x=0
Упростите выражение 3m(2m-1)-(m+3)(m-2)

Answer 1

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#1 

7x²+21x=0

7x*(x+3)=0

x*(x+3)=0

x=0           x₁=0

x+3=0       x₂=-3

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#2

3m(2m-1)-(m+3)(m-2)=

=6m²-3m-(m²-2m+3m-6)=

=6m²-3m-(m²+m-6)=

=6m²-3m-m²-m+6=

=5m²-4m+6

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Answer 2

7x²+21x=0
7x(х+3)=0
7х=0     х+3=0
х₁=0      х₂=-3
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3m(2m-1)-(m+3)(m-2)=6m²-3m-(m²+3m-2m-6)= 6m²-3m-m²-m+6=5m²-4m+6