Toán Lớp 7: Tính:
a, (27^2 . 8^5)/(6^6 . 32^3) + (3^4 . 4^4)/(2^2 . 6^2)
b, (4^5 . 9^4 – 2. 6^9)/(2^10 . 3^8 + 6^8 . 20)
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Toán Lớp 7: Tính:
a, (27^2 . 8^5)/(6^6 . 32^3) + (3^4 . 4^4)/(2^2 . 6^2)
b, (4^5 . 9^4 – 2. 6^9)/(2^10 . 3^8 + 6^8 . 20)
Comments ( 2 )
a)
(27^2 . 8^5)/(6^6 . 32^3)+(3^4 . 4^4)/(2^2 . 6^2)
=((3^3)^2 . (2^3)^5)/((2.3)^6 . (2^5)^3)+(3^4 . (2^2)^4)/(2^2 . (2.3)^2)
=(3^6 . 2^15)/(2^6 . 3^6 . 2^15)+(3^4 . 2^8)/(2^2 . 2^2 . 3^2)
=(3^6 . 2^15)/(2^21 . 3^6)+(3^4 . 2^8)/(2^4 . 3^2)
=(1.1)/(2^6 . 1)+(3^2 . 2^4)/(1.1)
=1/64+3^2 . 2^4
=1/64+9.16
=1/64+144
=1/64+9216/64
=9217/64
b)
(4^5 . 9^4-2.6^9)/(2^10 . 3^8+6^8 . 20)
=((2^2)^5 . (3^2)^4-2.(2.3)^9)/(2^10 . 3^8 + (2.3)^8 . 2^2 . 5)
=(2^10 . 3^8 – 2. 2^9 . 3^9)/(2^10 . 3^8 + 2^8 . 3^8 . 2^2 . 5)
=(2^10 . 3^8 – 2^10 . 3^9)/(2^10 . 3^8+2^10 . 3^8 .5)
=(2^10 . 3^8 .(1-3))/(2^10 . 3^8 . (1+5))
=(2^10 . 3^8 . (-2))/(2^10 . 3^8 . 6)
=(-1 . 2^11 . 3^8)/(6 . 3^8 . 2^10)
=(-1 . 2 . 1)/(6 . 1 . 1)
=-2/6
=-1/3