Question

Tính giá trị biểu thức

A=\(\dfrac{54^2-23^2}{\left(36,5\right)^2-\left(25,5\right)^2}\)

B=\(\dfrac{82^2-34^2}{\left(30,5\right)^2-\left(1,5\right)^2}\)

C=\(\dfrac{86^3-54^3}{32}+86.54\)

D=\(\dfrac{101^3+89^3}{190}-101.89\)

Answer 1

a,Ta có A=\(\dfrac{\left(54-23\right)\left(54+23\right)}{\left(36,5-25,5\right)\left(36,5+25,5\right)}=\dfrac{31.77}{11.62}=\dfrac{7}{2}\)

b,Ta có B=\(\dfrac{\left(82-34\right)\left(82+34\right)}{\left(30,5-1,5\right)\left(30,5+1,5\right)}=\dfrac{48.116}{29.32}=\dfrac{6.8.4.29}{29.8.4}=6\)

c,Ta có C=\(\dfrac{\left(86-54\right)\left(86^2+86.54+54^2\right)}{32}+86.54=86^2+86.54+54^2+86.54=\left(86+54\right)^2=19600\)