Cho a, b,c thỏa mãn a+b-2c=0 và 2ab-bc-ca=0 chứng minh a=b=c

Liesl grew 7/12 of a foot in one year. her little sister grew 1/3 of a foot during that same year. how much more did liesl grow than her little sister did

Find the y-intercept and x-intercept for the equation 5x-3y=60 what is the y-intercept

Liz had 140 pens and inna had 100 pens. after inna gave liz some pens, liz had 3 times as many pens as inna. how many pens did inna give liz?