Question

A is a point on the x-axis and B is (-7, 9). Distance between the points A and B is 15 units. Find the coordinates of point A.​

Answer 1

Answer:

-19 or 5

Step-by-step explanation:

we will take point a as (0,x) b as (-7,9) and distance as 15.

by inputting the distance formula we ll get the answer.

btw .. u just gave ur class 9th icse board exam today

Answer 2

$\Large{\textbf{\underline{\underline{According\:to\:the\:Question}}}}$

A is a point on x - axis

B = (-7, 9)

Coordinates on x - axis = (x, 0)

Now,

Assume

Coordinates of A = (x, 0)

Distance between them = 15 units

Using Formula we have

${\boxed{\sf\:{\sqrt{(x_{2}-x_{1})^2+(y_{2}-y_{1})^2}}}}$

So,

$\tt{\rightarrow AB=\sqrt{(-7-x)^2+(9-0)^2}=15}$

$\tt{\rightarrow AB=\sqrt{(-7)^2+x^2-2(-7)(x)+9^2}=15}$

$\tt{\rightarrow AB=\sqrt{49+x^2+14x+81}=15}$

$\tt{\rightarrow AB=\sqrt{x^2+14x+130}=15}$

Squaring :-

x² + 14x + 130 = 15²

x² + 14x + 130 = 225

x² + 14x + 130 - 225 = 0

x² + 14x - 95 = 0

x² + 19x - 5x - 95 = 0

x(x + 19) - 5(x + 19) = 0

(x - 5)(x + 19) = 0

⇒ x - 5 = 0

x = 5

x + 19 = 0

x = -19

⇒ x = 5 or x = - 19

Hence,

Coordinates of A are (5,0) , (-19,0)