4 + X + \(\frac{3}{4}\)= \(\frac{17}{2}\)
<=> X = \(\frac{17}{2}\)-\(\frac{3}{4}\)- 4
<=> X = \(\frac{15}{4}\)
vậy X =\(\frac{15}{4}\)
4 cong x cong 3 phan 4 bang 17 phan 2
Tim mot phan so biet rang neu cong them 4 vao tu so va giu nguyen mau so thi phan so moi bang 1,neu cong them 3 vao mau so va giu nguyen tuso thi duoc phan so moi bang 1/2
1phan 2 cong 1 phan 3 cong 1 phan 5 bang bao nhieu
tinh nhanh 4 phan 5 cong 2 phan 7 cong 11 phan 5 cong 12 phan 7 cong 1 phan 5
1 phan 6 cong 3 phan 4 cong 1 phan 8
Trung binh cong cua 2 phan so = 7/8 Nếu tang phan so thu hai len gap 3 lan thi trung binh cong cua chung =17/8 Tim 2 phan so do
cho phan so 3/5 .neu tu so cong them 6 thi mau sob phai cong thjem so nao de duoc phan so moi van bang 3/5
Cho phan so 5 phan 13.Tim mot so tu nhien de khi cong so do vao tu so va lay mau so tru di chinh so do ta duoc phan so moi bang phan so 4 phan 5.