Để B đạt GTLN thì \(8\left|15x-21+7\right|\)nhỏ nhất\(\Rightarrow\left|15x-21+7\right|\ge1\Rightarrow8.\left|15x-21+7\right|\ge8\)Max B=\(\dfrac{55}{24}\)khi x=1 hoặc x=\(\dfrac{13}{15}\)
tính:
(3\(\dfrac{1}{3}\): 3,2 +4,5 . 1\(\dfrac{31}{45}\)):(-21\(\dfrac{1}{2}\))
1. Tính ( hợp lý nếu có thể )
a, A = \(\dfrac{7,5-0,6+\dfrac{3}{7}+\dfrac{3}{13}}{2,75-2,2+\dfrac{11}{7}+\dfrac{11}{3}}\)
b, B = 26 : \(\left[\dfrac{3:\left(0,2-0,1\right)}{2,5.\left(0,8+1,2\right)}+\dfrac{\left(34,06-33,81\right).4}{6.84:\left(28,57-25,15\right)}\right]\)+ \(\dfrac{2}{3}\) : \(\dfrac{4}{21}\)
c, C = \(\left[\left(\dfrac{2}{193}-\dfrac{3}{386}\right).\dfrac{193}{17}+\dfrac{33}{34}\right]\) : \(\left[\left(\dfrac{7}{2001}+\dfrac{11}{4002}\right).\dfrac{2001}{25}+\dfrac{9}{2}\right]\)
d, D = \(\dfrac{0.8:\left(\dfrac{4}{5}.1,25\right)}{0.64-\dfrac{1}{25}}\) + \(\dfrac{\left(1.08-\dfrac{5}{25}\right):\dfrac{4}{7}}{\left(6\dfrac{5}{9}-3\dfrac{1}{4}\right).2\dfrac{2}{7}}\) + ( 11,2 . 0,5 ) : \(\dfrac{4}{5}\)
Giúp mk nha chỉ là tính toán thông thường tính ra là đc nhưng mà mk lại khó tính ra nên các bn giúp mk nha
Câu 1: Tinh
\(A=\left(\dfrac{3}{5}\right)^2.5^2-\left(2\dfrac{1}{4}\right)^3:\left(\dfrac{3}{4}\right)^3+\dfrac{1}{2}\)
\(B=\left[\dfrac{4}{11}.\left(\dfrac{1}{25}\right)^0+\dfrac{7}{22}.2\right]^{2010}-\left(\dfrac{1}{2^2}:\dfrac{8^2}{4^4}\right)^{2009}\)
\(\dfrac{7}{8}.\left(\dfrac{2}{12}+\dfrac{4}{10}\right)\)
\(\dfrac{3}{2}-\dfrac{5}{6}:\left(\dfrac{1}{2}\right)^2+\sqrt{4}\)
Câu 2: Tim x
\(2.x-\dfrac{5}{4}=\dfrac{20}{15}\)
\(\left(x+\dfrac{1}{3}\right)^3=\left(\dfrac{-1}{8}\right)\)
Tìm x , biết :
1, |\(\dfrac{3}{2}\)x + \(\dfrac{1}{2}\)| = | 4x - 1 |
2, | \(\dfrac{5}{4}\)x - \(\dfrac{7}{2}\) | - | \(\dfrac{5}{8}x+\dfrac{3}{5}\) | = 0
3, | \(\dfrac{7}{5}x+\dfrac{2}{3}\) | = | \(\dfrac{4}{3}x-\dfrac{1}{4}\) |
4, | \(\dfrac{7}{8}x+\dfrac{5}{6}\) | - | \(\dfrac{1}{2}x+5\) | = 0
Tìm x:
\(\left|x-3,2\right|\)+\(\left|21-\dfrac{1}{5}\right|\) = x-3
1,tìm x:
a,\(\dfrac{3}{4}-|2x+1|=\dfrac{7}{8}\)
b,\(2.|2x-3|=\dfrac{1}{2}\)
c,\(7,5-3.|5-2x|=-4,5\)
d,\(|x+\dfrac{4}{15}|-|-3,75|=-|-2,15|\)
giúp mình nha mọi người
Tìm x, biết \(\left|x+\dfrac{7}{9}\right|+\left|x+\dfrac{1}{3}\right|+\left|x+2\dfrac{8}{9}\right|=5x\)
a) \(\left[\left(-32,47\right)+68,12\right]+32,47\)
b) \(\left[\left(-61,8\right)+\left(-123,6\right)\right]+\left[83,6+61,8\right]\)
c) \(-\left(\dfrac{2}{7}+\dfrac{1}{3}-\dfrac{5}{6}\right)-\left(\dfrac{-9}{7}+\dfrac{14}{7}-\dfrac{1}{5}+\dfrac{5}{3}\right)\)
Tìm x, theo 3 cách:
a) \(\dfrac{x+1}{3}=\dfrac{3}{6}\)
b)\(\dfrac{2x+1}{3}=\dfrac{3}{6}\). c)\(\dfrac{2x-1}{4}=\dfrac{3}{8}\)
