Câu 1
a,cho biểu thức :(3x-5).(2x+11)-(2x+3).(3x+7)
Câu 2 Tìm x biết:
a,(3x+5).(2x-1)+(5-6x).(x+2)=x
b,(5x-3).(7x+2)-35x(x-1)=42
Câu 2
a,Giá trị x thoả mãn (10x+9).x-(5x-1)(2x+3)=8
b, Giá trị x thoả mãn x(x+1)(x+6)-x³=5x
c, Giá trị x thoả mãn 2x²+3(x-1)(x+1)=5x(x+1)
C1:
`(3x-5)(2x+11)-(2x+3)(3x+7)`
`=6x^2+33x-10x-55-(6x^2+14x+9x+21)`
`=6x^2+33x-10x-55-6x^2-14x-9x-21`
`=76`
C2:
a, `(3x+5)(2x-1)+(5-6x)(x+2)=x`
`<=>6x^2+7x−5+(−6x^2−7x+10)=x`
`<=>6x^2+7x−5−6x^2−7x+10=x`
`<=>5=x`
`<=>x=5`
b, `(5x-3)(7x+2)-35x(x-1)=42`
`<=>35x^2−11x−6-(35x^2−35x)=42`
`<=>35x^2−11x−6-35x^2+35x=42`
`<=>24x-6=42`
`<=>24x=48`
`<=>x=2`