Tinh bang cach thuan tien nhat
45 , 28 + 52 ,17 - 15,28 -12,17
(72,69 + 18,47) -(8,47 + 22,69)
Cac ban cuu minh voi khong minh chet day😓😓😓😓😓
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
a)15,27-4,18-2,09
=15,27-(4,18+2,09)
=15,27-6,27
=9
b)60-26,75-13,25
=60-(26,75+13,25)
=60-40
=20
c)38,25-18,25+21,64-11,64+9,93
=(38,25-18,25)+(21,64-11,64)+9,93
=20+10+9,93
=39,93
d)45+52,17-15,28-12,17
=45+(52,17-12,17)-15,28
=45+40-15,28
=69,72
e)(72,69+18,47)-(8,47+22,69)
=72,69+18,47-8,48-22,69
=(72,69-22,69)+(18,47-8,47)
=50+10
=60
a: \(60-26,75-13,25\)
\(=60-\left(26,75+13,25\right)\)
\(=60-40=20\)
b: \(38,25-18,25+21,64-11,64+9,93\)
\(=\left(38,25-18,25\right)+\left(21,64-11,64\right)+9,93\)
\(=20+10+9,93=39,93\)
c: \(45,28+52,17-15,28-12,17\)
\(=\left(45,28-15,28\right)+\left(52,17-12,17\right)\)
=30+40
=70
d: \(\left(72,69+18,47\right)-\left(8,47+22,69\right)\)
\(=72,69+18,47-8,47-22,69\)
\(=\left(72,69-22,69\right)+\left(18,47-8,47\right)\)
=50+10
=60
Phương trình hoành độ giao điểm (d) và (P):
\(x^2-2x-3=ax-a-3\)
\(\Leftrightarrow x^2-\left(a+2\right)x+a=0\)
\(\Delta=\left(a+2\right)^2-4a=a^2+4>0;\forall a\Rightarrow\) (d) luôn cắt (P) tại 2 điểm pb
Theo hệ thức Viet: \(\left\{{}\begin{matrix}x_A+x_B=a+2\\x_Ax_B=a\end{matrix}\right.\)
Mặt khác do A, B thuộc (d) nên: \(\left\{{}\begin{matrix}y_A=ax_A-a-3\\y_B=ax_B-a-3\end{matrix}\right.\)
\(y_A+y_B=0\)
\(\Leftrightarrow a\left(x_A+x_B\right)-2a-6=0\)
\(\Leftrightarrow a\left(a+2\right)-2a-6=0\)
\(\Leftrightarrow a^2-6=0\)
\(\Leftrightarrow a=\pm\sqrt{6}\)
Theo ĐLBTKL , ta có:
\(\text{ mAl+mCuo = mCu + mAl2O3}\)
\(\rightarrow\)\(\text{27 + 60= 40 + mAl2O3}\)
\(\rightarrow\)\(\text{27+60-40 = mAl2O3}\)
\(\rightarrow\)\(\text{mAl2O3 = 47(g)}\)
432,71-287,36-112,64 60-26,75-13,25 (72,69+18,47)-(8,47+22,69)
=432,71-(287,36+112,64) =60-(26,75-13,25) =72,69+18,47-8,47-22,69
=432,71-400 =60-40 =72,69+10-22,69
=32,71 =20 =50+10
=60
Câu 16.
Hình vẽ tương đối thôi nha!!!
Bảo toàn động lương ta có:
\(\overrightarrow{p}=\overrightarrow{p_1}+\overrightarrow{p_2}\)
\(\Rightarrow p^2=p_2^2-p_1^2\)\(\Rightarrow p_2=\sqrt{p^2+p_1^2}\)
\(\Rightarrow m_2\cdot v_2=\sqrt{\left(m_1+m_2\right)\cdot v+m_1\cdot v_1}\)
\(\Rightarrow0,3\cdot v_2=\sqrt{[\left(0,5+0,3\right)\cdot3]^2+(0,5\cdot4)^2}=3,124\)
\(\Rightarrow v_2=10,41\)m/s
a:45,28+52,17_15,28_12,17
=(45,28-15,28)+(52,17-12,17)
=30+40=70
45,28 + 52,17 - 15,28 - 12,17
= ( 45,28 - 15,28 ) + ( 52,17 - 12,17 )
= 30 + 40
= 70
( 72,69 + 18,47 ) - ( 8,47 + 22,69 )
= 72,69 + 18,47 - 8,47 - 22,69
= ( 72,69 - 22,69 ) + ( 18,47 - 8,47 )
= 50 + 10
= 60