1. Tìm x
a. -39 - (15+x) = 18
b. 31-(13+x) = 18.(-4)
c. 58-(47+3x)= -18 -2x
d. 37-(115+x) =188
GIẢI NHANH GIÚP MK NHÉ. MK CẦN GẤP
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a) 48 x 9 + 24 x 18 + 18 x 52
= 24 x 2 x 9 + 24 x 18 + 18 x 52
= 24 x 18 + 24 x 18 + 18 x 52
= 18 x (24+24+52)
=18 x 100
=1800
a﴿ 48 x 9 + 24 x 18 + 18 x 52
= 24 x 2 x 9 + 24 x 18 + 18 x 52
= 24 x 18 + 24 x 18 + 18 x 52
= 18 x ﴾24+24+52﴿
=18 x 100
=1800
các bn lm đến đâu cx dc miễn là lm hộ mk cái ạ, ai đang lm vào nhắn tin vs mk để mk bít nha
a; \(-\dfrac{8}{3}+\dfrac{7}{5}-\dfrac{71}{15}< x< -\dfrac{13}{7}+\dfrac{19}{14}-\dfrac{7}{2}\)
-\(\dfrac{19}{15}\) - \(\dfrac{71}{15}\) < \(x\) < -\(\dfrac{1}{2}\) - \(\dfrac{7}{2}\)
-6 < \(x\) < -4
vì \(x\) \(\in\) Z nên \(x\) = -5
a/x thuoc N*
b/(x-47)-155=0
(x-47) =0+155
x-47 =155
x =155+47
x =162
c/315+(146-x)=401
(146-x)=401-315
146-x =86
x =146-86
x =60
a) \(A=x^2-6x+10=\left(x^2-6x+9\right)+1=\left(x-3\right)^2+1\ge1\forall x\)
Dấu "=" xảy ra \(\Leftrightarrow x=3\). \(min_A=1\)
b) \(B=3x^2+x-2=3\left(x^2+\dfrac{1}{3}x-\dfrac{2}{3}\right)=3\left(x^2+\dfrac{1}{3}x+\dfrac{1}{36}-\dfrac{25}{36}\right)=3\left(x+\dfrac{1}{6}\right)^2-\dfrac{25}{12}\ge\dfrac{-25}{12}\forall x\)
Dấu "=" xảy ra \(\Leftrightarrow x=-\dfrac{1}{6}\). \(min_B=\dfrac{-25}{12}\)
c) \(C=\dfrac{4}{x^2}-\dfrac{3}{x}-1=\left(\dfrac{4}{x^2}-\dfrac{3}{x}+\dfrac{9}{16}\right)-\dfrac{25}{16}=\left(\dfrac{2}{x}+\dfrac{2}{3}\right)^2-\dfrac{25}{16}\ge\dfrac{-25}{16}\forall x\)
Dấu "=" xảy ra \(\Leftrightarrow x=-3\). \(min_C=\dfrac{-25}{16}\)
d) \(D=x^2+y^2-x+3y+7=\left(x^2-x+\dfrac{1}{4}\right)+\left(y^2+3y+\dfrac{9}{4}\right)+\dfrac{9}{2}=\left(x-\dfrac{1}{2}\right)^2+\left(y+\dfrac{3}{2}\right)^2+\dfrac{9}{2}\ge\dfrac{9}{2}\forall x\)
Dấu "=" xảy ra \(\Leftrightarrow\left\{{}\begin{matrix}x=\dfrac{1}{2}\\y=\dfrac{-3}{2}\end{matrix}\right.\). \(min_D=\dfrac{9}{2}\)
a) \(-39-\left(15+x\right)=18\)
\(-39-15-x=18\)
\(-54-x=18\)
\(x=-54-18\)
\(x=-72\)
vậy \(x=-72\)
b) \(31-\left(13+x\right)=18.\left(-4\right)\)
\(31-13-x=-72\)
\(18-x=-72\)
\(x=18+72\)
\(x=90\)
vậy \(x=90\)
c) \(58-\left(47+3x\right)=-18-2x\)
\(58-47-3x+2x=-18\)
\(11-x=-18\)
\(x=11+18\)
\(x=29\)
vậy \(x=29\)
d) \(37-\left(115+x\right)=188\)
\(37-115-x=188\)
\(-78-x=188\)
\(x=-78-188\)
\(x=-266\)
vậy \(x=-266\)
a)
\(-39-\left(15+x\right)=18\)
\(\Rightarrow15+x=-39-18\)
\(\Rightarrow15+x=-57\)
\(\Rightarrow x=-57-15\)
\(\Rightarrow x=-72\)
Vậy \(x=-72\)
b)
\(31-\left(13+x\right)=18.\left(-4\right)\)
\(\Rightarrow31-\left(13+x\right)=-72\)
\(\Rightarrow13+x=31-\left(-72\right)\)
\(\Rightarrow13+x=103\)
\(\Rightarrow x=103-13\)
\(\Rightarrow x=90\)
Vậy \(x=90\)