a) 43 + (9 – 21) = 317 – (x + 317)
b) 6x + 4x = 2010
c) x.(x+y) = 2
d) 5x – 3x – x = 20
a) 43 + (9 – 21) = 317 – (x + 317) b) 6x + 4x = 2010 c) x.(x+y) = 2 d) 5x – 3x – x = 20
By Abigail
By Abigail
a) 43 + (9 – 21) = 317 – (x + 317)
b) 6x + 4x = 2010
c) x.(x+y) = 2
d) 5x – 3x – x = 20
`a) 43 + (9 – 21) = 317 – (x + 317)`
`43 + -12 = 317 – (x + 317)`
` 31 = 317 – x + 317 `
` 31 = ( 317 – 317) + -x`
` 31 = -x`
⇒`-x = -31`
b) `6x + 4x = 2010`
`6.x + 4.x = 2010`
`( 6+4) . x = 2010`
` 10 . x = 2010`
` x = 2010 : 10`
` x = 201`
d)`5x – 3x – x = 20`
` 2x- x = 20`
`=> x=20`
a) 43 + (9 – 21) = 317 – (x + 317)
⇒ 43-12= 317 – x – 317
⇒ 317-x-317=43-12
⇒ -x = 31
⇒ x=-31
Vậy x= -31
b) 6x + 4x = 2010
⇒ 10x = 2010
⇒ x=201
Vậy x= 201
d) 5x – 3x – x = 20
⇒ x=20
Vậy x=20