\(\text{a,}4+8+12+...+80=\frac{\left(80+4\right).20}{2}=840\)

\(b,80-76+72-68+...+8-4=\left(80+72+64+...+8\right)-\left(76+68+60+4\right)\)

                                                                             \(=\frac{\left(80+8\right).10}{2}-\frac{\left(76+4\right).10}{2}\)

                                                                              \(40\)

Câu c tương tự câu b

a)(-12).(-5)-460=60-460= -400

b)(-5).4+(-200):(-5)= -20 + 40=20

c)(-150)-(-43)+120= -107 +120=13

d)(-85).13+(-85).17+(-85).70= -85 .(13+17+70)= -85.100= -8500

a)(-12).(-5)-460

=60-460

=-400

b)(-5).4+(-200):(-5)

=(-20)+40

=20

c)(-150)-(-43)+120

=(-150)+43+120

=(-150+120)+43

=(-30)+43

=13

d)(-85).13+(-85).17+(-85).70

=(-85).(13+17+70)

=-85.100

=-8500

C

c

C

a)-2-13+(-14)-19

= - 48

b) 221+4[(-5).8-4]

=221+4(-40-4)

=221+4(-44)

=221-176

=45

c)\(\left(-2\right)^3.\left(-2\right)^2+32\)

=\(-8\cdot4+32\)

\(=-32+32=0\)

d) \(-15\cdot12-8\cdot\left(-12\right)\)

\(=15\cdot\left(-12\right)-8\cdot\left(-12\right)\)

\(=\left(-12\right)\left(15-8\right)\)

\(=\left(-12\right)\cdot7\)

\(=-84\)

a) -2 - 13 + (-14) - 19 = -48

b) 221 + 4\([\left(-5\right).8-4]\)= 45

c) (-2)³.(-2)² + 32 = (-2)⁵ + 32 = -32 + 32 = 0

d) -15.12 - 8.(-12) = 15.(-12) - 8.(-12)

                             = (-12).(15 - 8)

                             = (-12).7 = -84

~ Học tốt ~

(-2)-13+(-14)-19

= (-2)+(-13)+(-14)-19

= (-15)+(-14)-19

= (-29)-19

= (-29)+(-19)

= (-48)

221+4[(-5).8-4]

= 225 [(-40)-4]

= 225 [(-40)+(-4)]

= 225 (-44)

= (-9900)

(-2)³.(-2)²+32

= (-2)⁵+32

= (-32) + 32

= 0

(-15).12-8.(-12)

= (-180)-(-96)

= (-84)

tick cho mình

= (-2)+(-13)+14-19

= (-15) +14-19

= (-1) - 19

= (-1) + (-19) =(-20)

= 221+4[(-40)-4]

= 221+4[(-40)+(-4)]

= 221+4 (-44)

= 221+(-176) =45

= (-8) . 4+32

= (-32) +32 = 0

= (-180) - (-96) = (-84)

tick cho mình

420 + 65 . 4 = ( x + 175 ) : 5 + 30 

=> ( x + 175 ) : 5 + 30 = 420 + 45 . 4 

=> ( x + 175 ) : 5 + 30 = 600 

=> ( x + 175 ) : 5 = 600 - 30 

=> ( x + 175 ) : 5 = 570 

=> x + 175 = 570 . 5 

=> x + 175 = 2850 

=> x = 2850 - 175 

=> x = 2675 

nha bn 

các câu khác tương tự nhé 

nhớ ủng hộ mik nha mn 

\(\text{Tìm x hở e????}\)

~~~~~~~~~

\(\text{420 + 65 . 4 = ( x + 175 ) : 5 + 30}\)

\(420+260=\left(x+175\right):5+30\)

\(680=\text{ ( x + 175 ) : 5 + 30}\)

\(\text{ ( x + 175 ) : 5 + 30=680}\)

\(\text{ ( x + 175 ) : 5 =680-30}\)

\((x+175):5=650\)

\(x+175=650:5\)

\(x+175=130\)

\(x=130-175\)

\(x=-45\)

\(\text{(32.15) : 2 = (x + 70) : 14 - 40}\)

\(480:2=\text{ (x + 70) : 14 - 40}\)

\(240\text{ = (x + 70) : 14 - 40}\)

\(\text{ (x + 70) : 14 =280}\)

\(x+70=3920\)

\(x=3920-70\)

\(x=3850\)

\(\text{x - 4867 = ( 175 . 2050 . 76) + 25 + 23}\)

\(\text{x - 4867 = ( 175 . 2050 . 76) + 48}\)

\(x-4867=27265000+48\)

\(x-4867=27265048\)

\(x=27265048+4867\)

\(x=27260015\)

\(\text{Hok giỏi nhé!~!!}\)