Question

1.tìm x biết

a,15-(3+x)+2x=19

b,(-58)-(19-58-x)=60

c,2(x-4)-3(x+5)=4

d,(2-3x)+(x-3)=(5x-1)-(5x-2)

2.Tính nhanh

a,A= -3752-(29-3632)-51

b,B=3542-(674-798)-(326+2798)

Answer 1

1. a, 15-(3+x)+2x=19
=> 15- 3 - x + 2x = 19
=> -x + 2x = 19 - 15 +3
=> ( -1 + 2 )x = 7
=> x = 7
b, (-58)-(19-58-x)=60
=> (-58)-(-39-x)=60
=> -58 +39 + x = 60
=> -19 + x = 60
=> x = 60 - (-19) = 79
c, 2(x-4)-3(x+5)=4
=> (2x - 8 )-(3x+15)= 4
=> 2x - 8 - 3x - 15 = 4
=> 2x - 3x = 4 + 15 + 8
=> - x = 27
=> x = -27
d, (2-3x)+(x-3)=(5x-1)-(5x-2)
=> 2 - 3x + x - 3 = 5x - 1 - 5x + 2
=> 2 - 3 - 3x + x = 5x - 5x - 1 +2
=> 2 - 3 - 3x + x = 1
=> - 3x + x = 1 - 2 + 3
=> -2x = 2
=> x= -1
=))))

Answer 2

2.

a,

A= -3752-(29-3632)-51

A= -3572-29+3632-51

A=(-3572+3632)-29-51

A=

Answer 3

1> a, 15 - ( 3 + x ) + 2 x = 19
=> 15 - 3 - x + 2x = 19
=> -x + 2x = 19 - 15 +3
=> ( -1 + 2 ) x = 7
=> x = 7
b, ( -58 ) - ( 19-58-x ) = 60
=> ( -58 ) - ( -39 – x ) = 60
=> -58 + 39 + x = 60
=> -19 + x = 60
=> x = 60 - ( -19 ) = 79
c, 2 ( x - 4 ) - 3 ( x+5 ) = 4
=> ( 2x - 8 ) - ( 3x + 15 ) = 4
=> 2x - 8 - 3x - 15 = 4
=> 2x - 3x = 4 + 15 + 8
=> - x = 27
=> x = -27
d, ( 2 - 3x ) + ( x - 3 ) = ( 5x - 1 ) - ( 5x – 2 )
=> 2 - 3x + x - 3 = 5x - 1 - 5x + 2
=> 2 - 3 - 3x + x = 5x - 5x - 1 +2
=> 2 - 3 - 3x + x = 1
=> - 3x + x = 1 - 2 + 3
=> -2x = 2
=> x= -1

Answer 4

1. a, 15-(3+x)+2x=19
=> 15- 3 - x + 2x = 19
=> -x + 2x = 19 - 15 +3
=> ( -1 + 2 )x = 7
=> x = 7
b, (-58)-(19-58-x)=60
=> (-58)-(-39-x)=60
=> -58 +39 + x = 60
=> -19 + x = 60
=> x = 60 - (-19) = 79
c, 2(x-4)-3(x+5)=4
=> (2x - 8 )-(3x+15)= 4
=> 2x - 8 - 3x - 15 = 4
=> 2x - 3x = 4 + 15 + 8
=> - x = 27
=> x = -27
d, (2-3x)+(x-3)=(5x-1)-(5x-2)
=> 2 - 3x + x - 3 = 5x - 1 - 5x + 2
=> 2 - 3 - 3x + x = 5x - 5x - 1 +2
=> 2 - 3 - 3x + x = 1
=> - 3x + x = 1 - 2 + 3
=> -2x = 2
=> x= -1