Question

Дано ар-пр а5=-25 d=1,4 Найти а3? а8?

Answer 1

A5=A1+(5-1)*d -25=A1+4*1.4 A1=-25-5.6 A1=-30,6 A3=-30,6+2*1,4 A3=-27,8 A8=-30,6+7*1,4 A8=-20,8

Answer 2

Solution for Finding a3 and a8

To find the values of a3 and a8, we can use the given information and solve for these variables.

Given: - ar-pr a5 = -25 - d = 1.4

We can use the formula for the nth term of an arithmetic progression: an = a1 + (n - 1)d

Finding a3

Using the given information, we can find a3 using the formula: a3 = a1 + (3 - 1)d

Substitute the given values: a3 = a1 + 2d

Finding a8

Similarly, we can find a8 using the formula: a8 = a1 + (8 - 1)d

Substitute the given values: a8 = a1 + 7d

Now, let's calculate the values of a3 and a8 using the given information.

Calculation

Given: - a5 = -25 - d = 1.4

Using the formula for a5: a5 = a1 + 4d

We can rearrange the formula to solve for a1: a1 = a5 - 4d

Substitute the given values: a1 = -25 - 4(1.4) a1 = -25 - 5.6 a1 = -30.6

Now, we can calculate the values of a3 and a8 using a1 and d.

Calculating a3

Using the formula: a3 = a1 + 2d

Substitute the calculated values: a3 = -30.6 + 2(1.4) a3 = -30.6 + 2.8 a3 = -27.8

Calculating a8

Using the formula: a8 = a1 + 7d

Substitute the calculated values: a8 = -30.6 + 7(1.4) a8 = -30.6 + 9.8 a8 = -20.8

Results

So, the values of a3 and a8 are: a3 = -27.8 a8 = -20.8