What is the radius of a circle whose equation is x2 + y2 + 8x – 6y + 21 = 0?

Asked by wiki @ 26/11/2020 in Mathematics viewed by 280 People

Answered by wiki @ 26/11/2020

we know that

the standard form of the equation of the circle is

$(x-h)^{2} +(y-k)^{2}=r^{2}$

where

(h,k) is the center of the circle

r is the radius of the circle

In this problem we have

$x^{2} +y^{2} +8x-6y+21=0$

Convert to standard form

Group terms that contain the same variable, and move the constant to the opposite side of the equation

$(x^{2}+8x) +(y^{2}-6y)=-21$

Complete the square twice. Remember to balance the equation by adding the same constants to each side.

$(x^{2}+8x+16) +(y^{2}-6y+9)=-21+16+9$

$(x^{2}+8x+16) +(y^{2}-6y+9)=4$

Rewrite as perfect squares

$(x+4)^{2} +(y-3)^{2}=4$

$(x+4)^{2} +(y-3)^{2}=2^{2}$

the center of the circle is $(-4,3)$

the radius of the circle is $2\ units$

therefore

the answer is

the radius of the circle is $2\ units$

What is the radius of a circle whose equation is x2 + y2 + 8x – 6y + 21 = 0? units

Asked by maham237 @ 24/12/2020 in Mathematics viewed by 304 persons

What is the radius of a circle whose equation is x2 y2 – 10x 6y 18 = 0?

Asked by maham237 @ 15/12/2020 in Mathematics viewed by 414 persons

Which explains how to find the radius of a circle whose equation is in the form x2 + y2 = z?

Asked by wiki @ 25/10/2020 in Mathematics viewed by 460 persons

Choose the equation that represents the solutions of 0 = 0.25x2 - 8x.

Asked by maham237 @ 25/12/2020 in Mathematics viewed by 279 persons

PLEASEE HELP ANYONE Choose the equation that represents the solutions of 0 = 0.25x^2 - 8x.

What is the general form of the equation of a circle with center at (a, b) and radius of length m?

Asked by maham237 @ 02/12/2020 in Mathematics viewed by 366 persons

A. x2 + y2 − 2ax − 2by + (a2 + b2 − m2) = 0 . . B.x2 + y2 + 2ax + 2by + (a2 + b2 − …

What should be taken away from 3x2-4y2+5xy+20 to obtain-x2-y2+6xy+20

Asked by admin @ 23/08/2021 in Math viewed by 297 persons

What should be taken away from 3x^2-4y^2+5xy+20 to obtain-x^2-y^2+6xy+20

Finding center and radius of a circle from an equation

Asked by admin @ 07/11/2021 in Mathematics viewed by 298 persons

Determine the equation of a circle with a center at (–4, 0) that passes through the point (–2, 1) by following the steps below. Use the distance formula to determine …

A radio station has a broadcast area in the shape of a circle with equation x^2+y^2=5 625

Asked by maham237 @ 25/12/2020 in Mathematics viewed by 295 persons

What is the general form of the equation for the given circle centered at o(0, 0)?.

Asked by maham237 @ 15/12/2020 in Mathematics viewed by 466 persons

What is the general form of the equation for the given circle centered at O(0, 0)? a) x2 + y2 + 41 = 0 b) x2 + y2 − 41 …

What is the general form of the equation for the given circle centered at o(0, 0)?

Asked by maham237 @ 15/12/2020 in Mathematics viewed by 368 persons

What is the general form of the equation for the given circle centered at O(0, 0)? a) x2 + y2 + 41 = 0 b) x2 + y2 − 41 …

Find the circumference of a circle whose radius is

Asked by admin @ 20/08/2021 in Math viewed by 333 persons

Find the circumference of the circle whose radius is: 21 cm

Find the radius of the circle whose diameter is

Asked by admin @ 17/08/2021 in Math viewed by 324 persons

Find the radius of a circle whose diameter is the following of the 18 cm

Find the radius of a circle whose diameter is 8cm

Asked by admin @ 04/08/2021 in Math viewed by 326 persons

Find the radius of the circle whose diameter is 8 cm Plz tell the answer in full explanation

What are the solutions to x2 8x 7 0 brainly

Asked by maham237 @ 11/07/2021 in Mathematics viewed by 295 persons

What are the solution(s) to the quadratic equation x2 – 25 = 0?

Asked by maham237 @ 19/12/2020 in Mathematics viewed by 264 persons

x = 5 and x = –5 x = 25 and x = –25 x = 125 and x = –125 no real solution

Unit 6 similar triangles homework 2 similar figures answer key

Asked by maham237 @ 25/06/2021 in Mathematics viewed by 18341 persons

All things algebra unit 7 polygons and quadrilaterals answer key

Asked by admin @ 30/09/2021 in Mathematics viewed by 8139 persons

Gina wilson all things algebra 2016 answer key unit 11

Asked by admin @ 07/11/2021 in Mathematics viewed by 5764 persons

Unit 1 geometry basics homework 4 angle addition postulate answers

Asked by maham237 @ 19/05/2021 in Mathematics viewed by 3929 persons

Unit 6 exponents and exponential functions homework 8 answer key

Asked by maham237 @ 03/01/2021 in Mathematics viewed by 3246 persons

The manager of a vacation resort believes that the ages

Asked by maham237 @ 19/07/2021 in Mathematics viewed by 2918 persons

What is 271 403 rounded to the nearest ten thousand

Asked by maham237 @ 24/07/2021 in Mathematics viewed by 2780 persons

Unit 1 geometry basics homework 3 angle relationships answer key

Asked by maham237 @ 21/05/2021 in Mathematics viewed by 2572 persons

Homework 2 parallelograms

Asked by maham237 @ 02/01/2021 in Mathematics viewed by 2491 persons

Why would a prism beat a sphere in a competition?

Asked by maham237 @ 13/01/2021 in Mathematics viewed by 2473 persons

John wants to send a letter to peter

Asked by maham237 @ 13/01/2021 in Mathematics viewed by 2458 persons

An artist sells a painting for 20.50 but uses 5.75

Asked by maham237 @ 24/06/2021 in Mathematics viewed by 2423 persons

Unit 4 congruent triangles homework 1 classifying triangles answer key

Asked by maham237 @ 10/06/2021 in Mathematics viewed by 2413 persons

Unit 4 congruent triangles homework 2 angles of triangles

Asked by maham237 @ 26/04/2021 in Mathematics viewed by 2068 persons

Compare the values of the 2s and 5s in 55220

Asked by maham237 @ 18/07/2021 in Mathematics viewed by 1788 persons