An arithmetic progression has the first term (a) and the common difference (d) a: write down the third, ninth and the twenty fifth terms of the progression
b: the arithmetic progression above is such that it is increasing and that the third, ninth and the twenty fifth terms form the first three consecutive terms of a geometric progression. The sum of the 7th and twice the sixth terms of the arithmetic progression is 78 calculate the first term and and the common difference of the arithmetic progression ​

addition

step-by-step explanation:

step-by-step explanation:

duck you

answer: (-8,4) are the coordinates of a

step-by-step explanation:

let the side of square abcd is x .

thus the area of square abcd is .

now, by the diagram area of triangle ead= 1/2 × ea × ad = 1/2 × ea × x

( because ad is the side of square)

and, according to the question,

the areas of square abcd and right ead are equal.

⇒

⇒ea=2x

thus, ea: ab=2: 1

therefore, point a divides line segment eb into the ratio 2: 1.

⇒ by sectional formula coordinates of a are,

=

=

=(-8, 4)

thus the coordinates of a are (-8,4)