\(\left(780^2-220^2\right):\left(125^2+150\cdot125+75^2\right)\)
\(=\dfrac{1000\cdot540}{200^2}\)
\(=\dfrac{10000\cdot54}{40000}=\dfrac{54}{4}=\dfrac{27}{2}\)
Tính nhanh
a,\(A=100^2-99^2+98^2-97^2+...+2^2-1^2\)
b,\(B=\left(20^2+18^2+...+2^2\right)-\left(19^2+17^2+....+3^2+1^2\right)\)
c,\(C=\frac{780^2-220^2}{125^2+150.125+75^2}\)
d,\(D=2.\left(a+5\right).\left(a+4\right)-\left(a+5\right)^2-\left(a^2-9a-17\right)\)với a=99
\(I\)Tính nhanh
\(a.127^2+146.127+73^2\)
\(b.9^8.2^8\left(18^4-1\right)\left(18^4+1\right)\)
\(c.100^2-99^2+98^2-97^2+...+2^2-1^2\)
\(d.\frac{780^2-220^2}{125^2+150.125+75^2}\)
\(II.\)Rút gọn các biểu thức
\(x^2\left(x+4\right)\left(x-4\right)-\left(x^2+1\right)\left(x^2-1\right)\)
\(\left(y-3\right)\left(y+3\right)\left(y^2+9\right)-\left(y^2+2\right)\left(y^2-2\right)\)
\(5\left(2x-1\right)^2+4\left(x-1\right)\left(x+3\right)-2\left(5-3x\right)^2\)
Tính Nhanh:
\(B=\frac{780^2-220^2}{125^2+150.125+75^2}\)
Tính nhanh :
A=100^2+98^2+96^2+....+2^2 - 99^2-97^2-95^2-....-1^2
B= 780^2-220^2/125^2+75^2+150.125
Tính nhanh:
7802 - 2202
1252 + 150.125 + 752
Tính nhanh :
a) ( 202 + 182 + 162 + ... + 42 ) - ( 192 + 172 + 152+ ... + 12 )
b) \(\frac{780^2-220^2}{125^2+150.125+75^2}\)
Tính nhanh, dùng hằng đẳng thức thứ 1;2;3
a) 1272 + 146 . 127 + 732
b) 98 . 28 - (184 - 1)(184 + 1)
c) \(\frac{780^2-220^2}{125^2+150.125+75^2}\)
tính nhanh
a)1272+146.127+732
b)98.28-(184-1)(184+1)
c)1802-2202/1252+150.125+752
Thu gọn \(\dfrac{20x^2+120x+180}{\left(3x+5\right)^2-4x^2}+\dfrac{5x^2-125}{9x^2-\left(2x+5\right)^2}-\dfrac{\left(2x+3\right)^2-x^2}{3\left(x^2+8x+15\right)}\)
