Question

the sum of 5th and 7th term of an ap is 52 and 10th term is 46 find the common difference of the AP ​

Answer 1

Answer:

As per question

S5+S7=52

5/2[2×a+4×d]+7/2[2a+6d]=52

5[a+2d]+7[a+3d]=52

5a+10d+7a+21d=52

12a+31d=52........(1)

Now we know,

a10=46

a+9d=46..........(2)

Now multiply 12 in (2)

12a+108d=452

Now subtract (2)-(1)

12a+108d-(12a+31d)=452-52

77d=400

d=400/77

Hope it helps you

Answer 2

Answer:

d = 5

Step-by-step explanation:

U5 + U7 = 2a + 10d = 52 , a + 5d = 26

U10 = a + 9d = 46

4d = 20 , d = 5