Question

tìm x biết

a) (7-x) - (25+7) = -25

b) x - [42 +(-28)] = -8

Answer 1

\(a,\left(7-x\right)-\left(25+7\right)=-25\)

\(\Rightarrow7-x-25-7=-25\)

\(\Rightarrow7-7-x=-25+25\)

\(\Rightarrow-x=0\)

\(\Rightarrow x=0\)

Answer 2

\(b,x-\left[42+\left(-28\right)\right]=-8\)

\(\Rightarrow x-14=-8\)

\(\Rightarrow x=-8+14=6\)

Answer 3

a) Ta có : ( 7 - x ) - ( 25 + 7 ) = -25

7 - x - 35 = -25

-28 - x = -25

x = -3

b) x - [ 42 + ( -28 ) ] = -8

x - 14 = -8

x = 6