Ko quy đồng mẫu các phân số, hãy tính hợp lý tổng sau:
B= 5/2x1 + 1/1x11 + 3/11x2 + 1/2x15 + 13/15x4
không qua quy đồng, hãy tính hợp lí tổng sau:
B = 5/2x1 + 4/1x11 + 3/11x2 + 1/2x15 + 13/15x4
B = 7x( 5/2x7 + 4/7x11 + 3/11x14 + 1/14x15 + 13/15x28 )
B = 7x(1/2 - 1/7 + 1/7 - 1/11 +....+ 1/15 - 1/28)
B = 7x(1/2 - 1/28)
B = 7x13/28
B = 13/4
Ai k mk mk k lai!
tinh : B=5/2x1 +4/1x11 + 3/11x2 +2/11x2 + 1/2x15 + 13/15x4
5/2\(\times\)1=\(\frac{5}{2\times1}hay=\frac{5}{2}\times1\)
Tính nhanh
A= 5/2x1 + 4/1x11 + 3/11x2 + 1/2x15 + 13/15x4
\(A=\frac{5}{2\times1}+\frac{4}{1\times11}+\frac{3}{11\times2}+\frac{1}{2\times15}+\frac{13}{15\times4}\)
\(=\frac{5}{2}+\frac{4}{11}+\frac{3}{22}+\frac{1}{30}+\frac{13}{60}\)
\(=\frac{13}{4}\)hoặc 3,25
Vậy A = 13/4 hoặc 3,25
tính hợp lí
5/2x1 + 4/1x11 + 3/11x2 + 1/2x15 + 13/15x4
Đặt \(A=\dfrac{5}{2.1}+\dfrac{4}{1.11}+\dfrac{3}{11.2}+\dfrac{1}{2.15}+\dfrac{13}{15.4}\)
\(\dfrac{A}{7}=\dfrac{5}{2.7}+\dfrac{4}{7.11}+\dfrac{3}{11.14}+\dfrac{1}{14.15}+\dfrac{13}{15.4}\)
\(\dfrac{A}{7}=\dfrac{1}{2}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{11}+...+\dfrac{1}{15}-\dfrac{1}{28}\)
\(\dfrac{A}{7}=\dfrac{1}{2}-\dfrac{1}{28}\)
\(\dfrac{A}{7}=\dfrac{13}{28}\)
\(A=\dfrac{13}{28}.7\)
\(A=\dfrac{13}{4}\)
Tính hợp lí:
B=5/2x1+4/1x11+3/11x2+1/2x15+13/15x4
B = 7x( 5/2x7 + 4/7x11 + 3/11x14 + 1/14x15 + 13/15x28 )
B = 7x(1/2 - 1/7 + 1/7 - 1/11 +....+ 1/15 - 1/28)
B = 7x(1/2 - 1/28)
B = 7x13/28
B = 13/4
B =7x (5/2.7 + 4/7.11 + 3/11.14 + 1/14.15 + 13/15.28)
B = 7x(1/2 - 1/7 + 1/7 - 1/11 +.....+ 1/15 - 1/28)
B = 7x(1/2 - 1/28)
B = 7 x 13/28
B = 13/4
Ai k mk mk k lại!!
bằng 13/4 nhá
có ai kết bạn với tui ko?????
5/(2x1) + 4/(1x11) + 3/(11x2) + 1/(2x15) + 13/(15x4) = ?
Tính nhanh 5/2x1 + 4/1x11 + 3/11x12 + 1/2x15 + 1/2x15 + 13/15x4
Giúp em nha mấy anh chị!!!!I love you%!!!!!!!!!!!!!!!!!!!!
A)4.25x58,47+41,53x4,25
B)B=5/2x1+4/1x11+3/11x2+1/2x15+13/15x4
a) 4,25 x 58,47 + 41,53 x 4,25
= 4,25 x ( 58,47 + 41,53 )
= 4,25 x 100
= 425
nhớ k đúng cho mik nha