9x^2 - 42x + 49 represents the area of a square. The area of the square is 64 square meters. What is x?

Science & Mathematics by Anonymous 2018-07-07 22:03:37

Social Science

7 answers

Anonymous

9x^2 - 42x + 49 = 64 9x^2 - 42x - 15 = 0 3x^2 - 14x - 5 = 0 [ 3x + 1 ] [ x - 5 ] = 0 x = 5 , x = -1/3
Anonymous

9x^2 - 42x + 49 = 64 9x^2 - 42x - 15 = 0 3x^2 - 14x - 5 = 0 (3x + 1)(x - 5) = 0 x = -1/3 or x = 5
Anonymous

4.
Anonymous

If it is a square then the area is 64 and the side is 8. If the quadratic 9x^2-42x+49= 64 then -1/3 and 5.
Anonymous

9x² - 42x + 49 = 64 ⇒ 9x² - 42x + 49 - 64 = 64 - 64 ⇒ 9x² - 42x - 15 = 0 ⇒ 3 (3x² - 14x - 5) = 0 ⇒ 3 (3x+1)(x-5) = 0 ⇒ x = -1 or x = 5 You cannot have a negative length, so you can ignore x=-1 and the solution is x = 5 meters...........ANS
Anonymous

(3x-7)^2 = 64 x = 5 m
Anonymous

(3x-7)^2 = 64 3x -7 = +/- 8 3x = 15 or -1 x = 5 or -1/3