x + 85 = 65 + 25
tim cach tinh nhanh nhat cho cac cau hoi :
25*25
35*35
45*45
55*55
65*65
75*75
85*85
95*95
tìm x a, \(\dfrac{x}{4}\) =\(\dfrac{15}{20}\) b, \(\dfrac{15}{x}\) = \(\dfrac{25}{35}\) c, \(\dfrac{x}{5}\)=\(\dfrac{26}{65}\) d, \(\dfrac{3}{x}\)=\(\dfrac{51}{85}\)
\(a,\dfrac{x}{4}=\dfrac{15}{20}\\ \Rightarrow\dfrac{x}{4}=\dfrac{3}{4}\\ \Rightarrow x=3\\ b,\dfrac{15}{x}=\dfrac{25}{35}\\ \Rightarrow\dfrac{15}{x}=\dfrac{5}{7}\\ \Rightarrow\dfrac{15}{x}=\dfrac{15}{21}\\ \Rightarrow x=21\\ c,\dfrac{x}{5}=\dfrac{26}{65}\\ \Rightarrow\dfrac{x}{5}=\dfrac{2}{5}\\ \Rightarrow x=2\\ d,\dfrac{3}{x}=\dfrac{51}{85}\\ \Rightarrow\dfrac{3}{x}=\dfrac{3}{5}\\ \Rightarrow x=5\)
a,x4=1520⇒x4=34⇒x=3b,15x=2535⇒15x=57⇒15x=1521⇒x=21c,x5=2665⇒x5=25⇒x=2d,3x=5185⇒3x=35⇒x=5
15h+45+25+35+65+75+85+95=?
15+45+25+35+65+75+85+95
=15+25+35+45+65+75+85+95
=(15+25+35+45)+(65+75+85+95)
=120 + 320
=440
tick nha Đức Dương
15+25+35+45+55+65+75+85+95=
15 + 25 + 35 + 45 + 55 + 65 + 75 + 85 + 95
= ( 15 + 85 ) + ( 25 + 75 ) + ( 35 + 65 ) + ( 45 + 55 ) + 95
= 100 + 100 + 100 + 100 + 95
= 495
Ngô Quang Ninh:
15 + 25 + 35 + 45 + 55 + 65 + 75 + 85 + 95
= (15 + 85) + (25 + 75) + (35 + 65) + (45 + 55) + 95
= 100 + 100 + 100 + 100 + 95
= 495
Tham khảo nha!
Tính nhanh:15+25+35+45+55+65+75+85
15 + 25 + 35 + 45 + 55 + 65 + 75 + 85
= (15 + 85) + (25 + 75) + (35 + 65) + (45 + 55)
= 100 + 100 + 100 + 100
= 400
15+25+35+45+55+65+75+85
=(15+85)+(25+75)+(35+65)+(45+55)
=100+100+100+100
=400
15+25+35+45+55+65+75+85
= ( 15+85) +( 25+75)+ ( 35+65)+( 45+55)
= 100+100+100+100=4 x 100 = 400
nhanh nhé
25-55(85+65)=5 các bạn có tin ko
5+15+25+35+45+55+65+75+85+95=?????????
= ( 5 + 95 ) + ( 15 + 85 ) + ( 25 + 75 ) + ( 35 + 65 ) + ( 45 + 55 )
= 100 + 100 + 100 + 100 + 100
= 5 x 100
= 500
tìm phân số bằng nhau
15/21 ; 51/85 ; 26/39 ; 39/65 ; 25/35 ; 38/27
\(\dfrac{51}{85}=\dfrac{39}{65}\)
\(\dfrac{15}{21}=\dfrac{25}{35}\)
a,-65.(87-17)-85.(17-65)
b,[3.(-2)-(-8).(-7).(-2).(-5)
Câu 2:tTinh giá trị biểu thức
a,(-55).(-25).(-x) với =-8
b,(-1).(-2).(-3).(-4).(-5).x với x=10
Câu 3:Cho x=-3; b=-5. Tính tích 5a2 b3
5a2v và b3 là 5a mũ 2 và b mũ ba nhé