Toán Lớp 8: tính nhanh a,153^2+94.153+47^2 b,126^2-152.126+5776 c,3^8.5^8-(15^4-1)915^4+1) d,(2+1)(2^2+1)(2^4+1)-(2^20+1)+1

Question

Toán Lớp 8:  tính nhanh a,153^2+94.153+47^2 b,126^2-152.126+5776 c,3^8.5^8-(15^4-1)915^4+1) d,(2+1)(2^2+1)(2^4+1)....(2^20+1)+1

tuyetanhthu · Answer

a, 153&sup2; +  94.153+47&sup2;        = 153&sup2; + 2.47.153 + 47&sup2;        = ( 153+47 )&sup2;        = 200&sup2; = 40000     b, 126&sup2; - 152.126 + 5776       = 126&sup2; - 2.76.126 + 76&sup2;      = ( 126 - 76 )&sup2;      = 50&sup2; = 2500   c,  $3^{8}$ . $5^{8}$ -( $15^{4}$ -1 )( $15^{4}$+1 )        = $(3.5)^{8}$ - $15^{8}$ + 1        = $15^{8}$ - $15^{8}$ + 1        = 1     d,

buithaianh98 · Answer

Giải đáp v&agrave; giải th&iacute;ch c&aacute;c bước giải:     a) 153^2+99.153+47^2   = 153^2+2.47.153+47^2   = (153+47)^2   =200^2   =40000   b) 126^2-152.126+5776   = 126^2-2.76.126+76^2   = (126-76)^2   = 50^2   = 2500   c)3^8.5^8-(15^4-1).(15^4+1)   = 15^8-[(15^4)^2-1^2]   = 15^8-15^8+1   =1   d) (2+1).(2^2+1).(2^4+1)...(2^32+1)+1   = 1.(2+1).(2^2+1).(2^4+1)...(2^32+1)+1   = (2-1).(2+1).(2+1).(2^4+1)...(2^32+1)+1   = (2^2-1).(2^2+1).(2^4+1)...(2^32+1)+1   = (2^4-1).(2^4+1)...(2^32+1)+1   = (2^8-1)...(2^32+1)+1   = (2^32-1).(2^32+1)+1   = 2^64-1+1   = 2^64