\(=\left(x-y\right)\left(x+y\right)-7\left(x-y\right)\)

\(=\left(x-y\right)\left(x+y-7\right)\)

\(=100^2=10000\)

\(=x^2+2\cdot6\cdot x+6^2=\left(x+6\right)^2\\ =\left(94+6\right)^2=100^2=10000\)

a. x\(^2\) + 12x + 36 = x\(^2\) + 2 . x . 6 + 6\(^2\) = ( x + 6 )\(^2\)

thay x = 94 vào biểu thức, ta có:

( 94 + 6 )\(^2\) = 100\(^2\) = 10000

vậy x + 12x + 36 = 10000 tại x = 94.

\(a,=3x^2+12x-7x+20+2x^3-3x^2-2x^3-5x=20\)

giải chi tiết đc ko ạ?như vậy misha ms bt cách làm^^

\(3x+2\left(5-x\right)=0\Leftrightarrow3x+10-2x=0\Leftrightarrow x=-10\)

bạn giải chi tiết giúp misha đc ko?^^

\(3x^2-3x\left(x-2\right)=36\\ \Leftrightarrow3x^2-\left(3x^2-6x\right)=36\\ \Leftrightarrow3x^2-3x^2+6x=36\\ \Leftrightarrow6x=36\\ \Leftrightarrow x=36:6\\ \Leftrightarrow x=6\)

\(3x+2\left(5-x\right)=0\\ \Rightarrow3x+\left(10-2x\right)=0\\ \Rightarrow3x+10-2x=0\\ \Rightarrow\left(3x-2x\right)+10=0\\ \Rightarrow x+10=0\\ \Rightarrow x=-10\)

\(=x^2+8x-x-8=x\left(x+8\right)-\left(x+8\right)=\left(x+8\right)\left(x-1\right)\)

\(x^2+8x-x-8=8\left(x-1\right)+x\left(x-1\right)=\left(8+x\right)\left(x-1\right)\)

\(=-5x^2+15x+x-3=-5x\left(x-3\right)+\left(x-3\right)=\left(1-5x\right)\left(x-3\right)\)

\(\Leftrightarrow x^2+3x+2-x^2+6x-9=11\)

hay x=2