Question

Tính nhanh

a, −57(75−36)−75(36−57)−57(75−36)−75(36−57)

b, 19−42(−19)+38.5

Tìm x

a,7x(x-10)=0

b, (4-x) . ( 2x+6)=0

c, -12(x-5) + 7 . ( 3-x ) =5

Answer 1

Bài 1:Tính

a, \(-57\left(75-36\right)-75\left(36-57\right)-57\left(75-36\right)-75\left(36-57\right)\)

\(=-114\left(75-36\right)-150\left(36-57\right)\)

\(=-144.39-150.\left(-21\right)\)

\(=-5616+3150=-2466\)

b, \(19-42\left(-19\right)+38.5\)

\(=19+42.19+19.2.5\)

\(=19.\left(1+42+10\right)=19.53=1007\)

Chúc bạn học tốt!!!

Answer 2

7x-(x-10)=0

7x^2-70x=0

7(x-10)x=0

(x-10)x=0:7

(x-10)x=0

x-10=0:x (Vì 0: cho 1 số b.kì thì đều=0)

x-10=0

x=10