A=1*2*3*4*5*6*7*8*9 thay * boi cach dau + hoac - de gia tri cua A=-4
thấy dau sao (.) biểu thức
1*2*3*4*5*6*7*8*9 boi cac dau cong tru de gia tri cua bieu thuc =
a)-13 b)-4
cho bieu thuc:
A=(6-2/3+1/2)-(5+5/3-3/2)-(3-7/3+5/2)
hay tinh gia tri cua A theo hai cach
cach 1:truoc het tinh gia tri tung bieu thuc trong ngoac
cach 2:bo dau ngoac roi nhom cac so hang thich hop
C1: \(A=\left(\frac{36}{6}-\frac{4}{6}+\frac{3}{6}\right)-\left(\frac{150}{30}+\frac{50}{30}-\frac{45}{30}\right)-\left(\frac{18}{6}-\frac{14}{6}+\frac{15}{6}\right)\)
\(=\frac{35}{6}-\frac{155}{30}-\frac{19}{6}=\frac{35}{6}-\frac{31}{6}-\frac{19}{6}=-\frac{15}{6}=-2\frac{1}{2}\)
C2: \(6-\frac{2}{3}+\frac{1}{2}-5-\frac{5}{3}+\frac{3}{2}-3+\frac{7}{3}-\frac{5}{2}\)
\(=\left(6-5-3\right)-\left(\frac{2}{3}+\frac{5}{3}-\frac{7}{3}\right)+\left(\frac{1}{2}+\frac{3}{2}-\frac{5}{2}\right)\)
\(=-2-0-\frac{1}{2}=-2\frac{1}{2}\)
Tinh gia tri bieu thuc bang cach thuan tien nhat :
A= 1/10 x 2/9 x 3/8 x 4/7 x 5/6 x 6/5 x 7/4 x 8/3 x 9/2
dat dau ngoac 1 cach thich hop nhat de tinh cac tong dai so sau :
a, 834 - 268 +2365 - 1834
b, 13 - 12 + 11 + 10 - 9 +8 -7 - 6 +5 - 4 +3 +2 - 1
dat dau ngoac 1 cach thich hop nhat de tinh cac tong dai so sau :
a, 834 - 268 +2365 - 1834
b, 13 - 12 + 11 + 10 - 9 +8 -7 - 6 +5 - 4 +3 +2 - 1
dat dau ngoac 1 cach thich hop nhat de tinh cac tong dai so sau :
a, 834 - 268 +2365 - 1834
b, 13 - 12 + 11 + 10 - 9 +8 -7 - 6 +5 - 4 +3 +2 - 1
Tinh gia tri cua cac bieu thuc sau theo 1 cach hop li
a, A= 1/3 × -6/13 × -9/10 × -13/36
b, B= -1/3 × -15/17 × 34/45
c, C=1/3 × 4/5 + 1/3 × 6/5 + 2/3
d, D= -5/6 × 4/19 + -7/12 × 4/19 - 40/57
e, E= 3/7 × 9/26 - 1/14 × 1/13 - 1/7
a, \(A=\dfrac{1}{3}.\dfrac{-6}{-3}.\dfrac{-9}{10}.\dfrac{-13}{36}\)
\(A=\dfrac{1.\left(-6\right).\left(-9\right).\left(-13\right)}{3.13.10.36}\)
\(A=\dfrac{-1}{10.2}\)
\(A=\dfrac{-1}{20}\)
b, \(B=\dfrac{-1}{3}.\dfrac{-15}{17}.\dfrac{34}{45}\)
\(B=\dfrac{\left(-1\right).\left(-15\right).34}{3.17.45}\)
\(B=\dfrac{2}{3.3}\)
\(B=\dfrac{2}{9}\)
c, \(C=\dfrac{1}{3}.\dfrac{4}{5}+\dfrac{1}{3}.\dfrac{6}{5}+\dfrac{2}{3}\)
\(C=\dfrac{1}{3}.\left(\dfrac{4}{5}+\dfrac{6}{5}\right)+\dfrac{2}{3}\)
\(C=\dfrac{1}{3}.2+\dfrac{2}{3}\)
\(C=\dfrac{2}{3}+\dfrac{2}{3}\)
\(C=\dfrac{4}{3}\)
d, \(D=\dfrac{-5}{6}.\dfrac{4}{19}+\dfrac{-7}{12}.\dfrac{4}{19}-\dfrac{40}{57}\)
\(D=\dfrac{4}{19}.\left(\dfrac{-5}{6}+\dfrac{-7}{12}\right)-\dfrac{40}{57}\)
\(D=\dfrac{4}{19}.\dfrac{-17}{12}-\dfrac{40}{57}\)
\(D=\dfrac{-17}{57}-\dfrac{40}{57}\)
\(D=\dfrac{-57}{57}=-1\)
e, \(E=\dfrac{3}{7}.\dfrac{9}{26}-\dfrac{1}{14}.\dfrac{1}{13}-\dfrac{1}{7}\)
\(E=\dfrac{3}{7}.\dfrac{9}{26}-\left(\dfrac{1}{14}.\dfrac{1}{13}+\dfrac{1}{7}\right)\)
\(E=\dfrac{3}{7}.\dfrac{9}{26}-\left(\dfrac{1}{182}+\dfrac{1}{7}\right)\)
\(E=\dfrac{3}{7}.\dfrac{9}{26}-\dfrac{27}{182}\)
\(E=\dfrac{27}{182}-\dfrac{27}{182}\)
\(E=0\)
tim gia tri cua bieu thuc
A=1-2-3-4+5-6-7-8+9-10-11-12+...........+97+98-99-100
Tinh gia tri cua bieu thuc:
a, 4+11/8-5/6=
b, (1/2+4/7)-(3/7-3/10)=
\(4+\frac{11}{8}-\frac{5}{6}=\frac{96+33-20}{24}=\frac{109}{24}\)
\(\left(\frac{1}{2}+\frac{4}{7}\right)-\left(\frac{3}{7}-\frac{3}{10}\right)=\frac{1}{2}+\frac{4}{7}-\frac{3}{7}+\frac{3}{10}\)
\(\left(\frac{1}{2}+\frac{3}{10}\right)+\left(\frac{4}{7}-\frac{3}{7}\right)=\frac{4}{5}+\frac{1}{7}=\frac{28+5}{35}=\frac{33}{35}\)
ban Chitanda Eru oi to bao nhung ma nhan voi bao nhieu ma ra duoc 96