How do you solve #7 - 7x = (4x + 9)(x - 1)#?

1 Answer
Nov 12, 2015

Answer:

x = -4 , 1

Explanation:

7 - 7x = (4x + 9) (x - 1)
or, 7 - 7x = 4x((x-1) + 9(x-1)
or, 7 - 7x = 4#x^2# -4x +9x -9
or, 0 = 4#x^2#+5x +7x-7-9
or, 4#x^2#+12x-16 = 0
0r, 4#x^2#+(16-4)x-16 = 0
or, 4#x^2#+16x -4x-16 = 0
or, 4x(x+4) - 4(x+4) = 0
or, (x+4) (4x -4) = 0
Either (x+4) = 0
x = -4
Or, (4x-4) = 0
or, 4x =4
or, x = #4/4#
or, x = 1
Hence x = -4 , 1