8*х-4*(х-4)=21 помогите плиз)
8 * X - 4 * ( X - 4 ) = 21 8X - 4X + 16 = 21 4X = 21 - 16 4X = 5 X = 5 : 4 X = 1,25
8х-4х+16=21; 4х=21-16; 4х=5; х=1,25