bài 1
:\(-15.67-15.\left(-33\right)-66.15\)
\(=15.\left(-67\right)-15.\left(-33\right)-15.66\)
\(=15.\left(-67+33-66\right)\)
\(=15.\left(-100\right)\)
\(=-1500\)
bài 2.
\(\left(x-2\right)^2-\left|-7\right|=9\)
\(=\left(x-2\right)^2\)
\(a,\left(x-2\right)^2-|-7|=9\)
\(\left(x-2\right)^2-7=9\)
\(\left(x-2\right)^2=16\)
\(\left(x-2\right)^2=\sqrt{16}=4^2\)
\(Th1:x-2=4\Leftrightarrow x=6\)
\(Th2:x-2=-4\Leftrightarrow x=-2\)
\(b,\left(x+4\right)\left(x^2-9\right)=0\)
\(Th1:x+4=0\Leftrightarrow x=-4\)
\(x^2-9=0\Leftrightarrow x^2=9\Leftrightarrow x=\pm9\)
1,\(\left(-15\right)\cdot67-15\cdot\left(-33\right)-66\cdot15\)
\(=15\left(-67+33-66\right)=15\cdot\left(-100\right)=-1500\)
2
a,\(\left(x-2\right)^2-\left|-7\right|=9\)
\(\Leftrightarrow\left(x-2\right)^2-7=9\)
\(\Leftrightarrow\left(x-2\right)^2=16\)
\(\Leftrightarrow\orbr{\begin{cases}x-2=4\\x-2=-4\end{cases}\Leftrightarrow}\orbr{\begin{cases}x=6\\x=-2\end{cases}}\)
vậy...
b,\(\left(x+4\right)\left(x^2-9\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x+4=0\\x^2=9\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=-4\\x=\pm3\end{cases}}\)
vậy ...
thực hiện phép tính
=(-15).67+15.33-66.15=(-15)(67-33+66)=(-15)100=-1500
tìm x
a, x^2-4x+4-7-9=0
x^2-4x-12=0
(x-6)(x+2)=0
(=) x=6;-2
b, (x+4)(x-3)(x+3)=0
x=-4;3;-3
