Question

[Phan Bá Quân]

Tìm x

a) 4x - 5(-3 + x) = 7

b) -4 (x + 1) + 8 (x - 3) = 24

c) 7(x - 9)-5(6 - x) = -6 + 11x

Answer 1

[Bùi Bảo Châu]

a)4x-5(-3+x)=7<=>4x+15-5x=7<=>4x-5x=7-15<=>-x=-8<=>x=8

b)-4(x+1)+8(x-3)=24

<=>-4x-4+8x-24=24

<=>-4x+8x=24+24+4

<=>4x=52<=>x=13

c)7(x-9)-5(6-x)=-6+11x

<=>7x-63-30+5x=-6+11x

<=>7x+5x-11x=-6+63+30

<=>x=87