Tìm số nguyên x,biết:
a) 2x-17=-51
b) 5x-(3x+12)=-40
c) (7x-12)-(120+4x)=-9
Tìm số nguyên x,biết: a) 2x-17=-51 b) 5x-(3x+12)=-40 c) (7x-12)-(120+4x)=-9
By Serenity
By Serenity
Tìm số nguyên x,biết:
a) 2x-17=-51
b) 5x-(3x+12)=-40
c) (7x-12)-(120+4x)=-9
Đáp án:
a) 2x-17=-51
⇔ 2x = -51+17
⇔ 2x = -34
⇔ x = -17
b) 5x-(3x+12)=-40
⇔ 5x-3x-12=-40
⇔ 2x-12=-40
⇔ 2x=-28
⇔ x=-14
c) (7x-12)-(120+4x)=-9
⇔ 7x-12-120-4x=-9
⇔ 3x-132= -9
⇔ 3x=123
⇔ x=41
a. 2x-17=-51
⇔ 2x = -51 +17
⇔ 2x = -34
⇔ x = -17
b. 5x-(3x+12)=-40
⇔ 5x – 3x – 12 = -40
⇔ 2x = -40 + 12
⇔ 2x = -28
⇔ x = -14
c. (7x-12)-(120+4x)=-9
⇔ 7x – 12 – 120 – 4x = -9
⇔ 3x – 132 = -9
⇔ 3x = -9 + 132
⇔ 3x = 123
⇔ x = 41