\(\left(-2\right)\left(3+5\right)\)
\(=\left(-2\right).8\)
\(=-16\)
(-2).(3+5)
=(-2).8
=(-16)
4 [-2(8:4)+15(-3)-(-12)
3(25:5-14:2)-5(6:2)
[-15:(-3)]-3[2(5-9):3]
-16:(-4)[7-2(15:3)]
-7[8-3(14:7)-12:(-4)]-3(-2)
2[3-9:(-3)+2(5-7)]-18:(-9)
-16:(-8)+5[3-15:5+2] (-3+4)
4[-2(8:4)+15:(-3)-(-12)
3(25:5-14:2)-5(6:2)
[-15:(-3)]-3[2(5-9):3)]
-16:(-4)[7-2(15:3)]
-7[8-3(14:7)-12:(-4)]-3(-2)
2[3-9:(-3)+2(5-7)]-18:(-9)
-16:(-8)+5[3-15:5+2] (-3+4)
1/ -7(5-x)-2(x-10)=15
2/ 4(x-5)-3(x+7)= -19
3/ 4(2-x)+3(x-5)=14
4/ 7(x-9)-5(6-x)=-6+11x
5/ -7(3x-5)+2(7x-14)=28
6/ 5(4-x)-7(-x+2)=4-9+3
7/ 4x-5(-3+x)=7
8/ 5(x-7)+10(3-x)=20
9/ 7(5-x)+5(x-2)=15
Tính nhanh:
a) \(P=\frac{3}{2.5}+\frac{3}{5.8}+\frac{3}{8.11}+...+\frac{3}{17.20}\)
b) \(Q=\frac{5^2}{1.6}+\frac{5^2}{6.11}+\frac{5^2}{11.16}+...+\frac{5^2}{26.31}\)
-3/4+2/7+(-1)/4+3/5+5/7
Viết các tích sau dưới dạng một lũy thừa :
a) \(\left(-5\right).\left(-5\right).\left(-5\right).\left(-5\right).\left(-5\right)\)
b) \(\left(-2\right).\left(-2\right).\left(-2\right).\left(-3\right).\left(-3\right).\left(-3\right)\)
( 1+ 1/2 ) . ( 1+ 1/3 ) . ( 1+ 1/4 )
1/5 : 1/10 - 1/3 ( 6/5 - 9/4 )
-7/8 : 21/16 - 3/5 . ( 1/5 - 7/10 )
3.(-5+6)-4.(3-2)
3.(-5+6)-4.(3-2)
tìm x,y,z biết x(3-1)=2(y+2);4(y+2)=5(z-3) và 2x+3y-4z=205
