Question

1.Tính :

145 + 55

13 + 50 + 37

92 + 56 - 48

2.Tìm x :

6x + x² = -9

Answer 1

đây mà là toán 8 hả bn

Answer 2

1.

145+55=200

13+50+37=100

92+56-48=100

2.\(6x+x^2=-9\Leftrightarrow x\left(6+x\right)=-9\Leftrightarrow\hept{\begin{cases}x=-9\\6+x=-9\end{cases}\Leftrightarrow\hept{\begin{cases}x=-9\\x=-15\end{cases}}}\)

k mk nhé

Answer 3

1. 

\(145+55=200\)

\(13+50+37=63+37=100\)

\(92+56-48=148-48=100\)

2.

\(6x+x^2=-9\)

\(x^2+6x+9=0\)

\(\left(x+3\right)^2=0\)

\(\Leftrightarrow x+3=0\)

\(x=-3\)