a) Áp dụng BĐT \(\left|a\right|+\left|b\right|\ge\left|a+b\right|\) ta có:

\(\left|x-1\right|+\left|x+3\right|=\left|1-x\right|+\left|x+3\right|\ge\left|1-x+x+3\right|=4\)

Đẳng thức xảy ra \(\Leftrightarrow\left\{{}\begin{matrix}1-x\ge0\\x+3\ge0\end{matrix}\right.\)

\(\Leftrightarrow-3\le x\le1\)

Vậy,..................................................................................................................................

Ơ thế sao t lại sai T GIỐNG NÓ MAH

m + 2 + m + 4 + m + 6 + m + 8 = 432

M = 2 + 4 + 6 + 8

M = 20

M = 432 - 20

M = 412

M = 412 : 4

M = 13

Vậy m + 2 + m + 4 + m + 6 + m 8 = 432; kết luận 13 + 2 + 13 + 4 + 13 + 6 + 8

Dễ

=(2+8)+(4+6)+(mx4)=432

=10+10+mx4=432

=20+m=108

=108-20

= 88

Học tốt!

M=1.2+2.3+3.4+...+212.213⇒3M=1.2.(3−0)+2.3.(4−1)+3.4.(5−2)+...+212.213.(214−211)=1.2.3−0.1.2+2.3.4−1.2.3+3.4.5−2.3.4+...+212.213.214−211.212.213=212.213.214=9663384⇒M=3221128M=1.2+2.3+3.4+...+212.213⇒3M=1.2.(3−0)+2.3.(4−1)+3.4.(5−2)+...+212.213.(214−211)=1.2.3−0.1.2+2.3.4−1.2.3+3.4.5−2.3.4+...+212.213.214−211.212.213=212.213.214=9663384⇒M=3221128

Chuyển trái sang phải rùi tìm M 

Ta có: -8+x^4-6x^4-M=7-x^4+9x^4

=>-8-5x^4-M=7-8x^4

=>M=-8-5x^4-7-8x^4

=>M=-15+3x^4

Vậy.......

\(a,M\left(-2;2\right)\in\left(d\right)\Leftrightarrow-2\left(m-2\right)+1=2\Leftrightarrow m=\dfrac{3}{2}\\ b,N\left(-3;4\right)\in\left(d\right)\Leftrightarrow-3\left(m-2\right)+1=4\Leftrightarrow m=1\\ c,\left(d\right)\cap Ox=\left(5;0\right)\Leftrightarrow5\left(m-2\right)+1=0\Leftrightarrow m=\dfrac{9}{5}\\ d,\left(d\right)\cap Oy=\left(0;-2\right)\Leftrightarrow1=-2\Leftrightarrow m\in\varnothing\\ e,\left(d\right)//\left(d'\right)\Leftrightarrow m-2=3\Leftrightarrow m=5\)

Ta có : \(m^2< 4\)

=> \(-2< m< 2\)

\(m:0,25+m.4+m:0,25=45,7\)

<=>\(m.4+m.4+m.4=45,7\)

<=>\(m.\left(4+4+4\right)=45,7\)

<=>\(12m=45,7\)

<=>\(m=3,808\left(3\right)\)

m:0,25+m.4+m:0,25=m.4+m.4+m.4=3.(m.4)=45,7

m.4=457/30=>m=457/120