SOLUTION: I would be grateful if you could kindly help me to get a step by step solution to following quadratic equation
Solve: (2x+1)(2x+3)(x-1)(x-2) = 150
Thanks & Regards,
Vijayan
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-> SOLUTION: I would be grateful if you could kindly help me to get a step by step solution to following quadratic equation
Solve: (2x+1)(2x+3)(x-1)(x-2) = 150
Thanks & Regards,
Vijayan
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Question 713081: I would be grateful if you could kindly help me to get a step by step solution to following quadratic equation
Solve: (2x+1)(2x+3)(x-1)(x-2) = 150
Thanks & Regards,
Vijayan C
(2x+1)(2x+3)(x-1)(x-2) = 150
FOIL out the first two parentheses on the left
(4x²+8x+3)(x-1)(x-2) = 150
FOIL out the last two parentheses on the left
(4x²+8x+3)(x²-3x+2) = 150
You have to use a generalized version of FOIL", which is:
(F+M+L)(F+M+L) = FF+FM+FL+MF+MM+ML+LF+LM+LL
Where F means the first term, M means the middle term,
and L means the last term:
(4x²)(x²)+(4x²)(-3x)+(4x²)(2)+(8x)(x²)+(8x)(-3x)+(8x)(2)+(3)(x²)+(3)(-3x)+(3)(2)
4x4-12x³+8x²+8x³-24x²+16x+3x²-9x+6 = 150
4x4-4x³-13x²+7x-144 = 0
You can factor x² out of the first two terms:
x²[4x²-4x]-13x²+7x-144 = 0
Complete the square in the bracket by adding 1 and subtracting
1 inside the bracket:
x²[4x²-4x+1-1]-13x²+7x-144 = 0
Factor the first three terms inside the bracket as a perfect
square:
x²[(2x-1)²-1]-13x²+7x-144 = 0
Distribute the x² to remove the bracket:
x²(2x-1)²-x²-13x²+7x-144 = 0
Combine the x² terms
x²(2x-1)²-14x²+7x-144 = 0
Factor -7x out of the -14x²+7x
x²(2x-1)²-7x(2x-1)-144 = 0
The first term can be written [x(2x-1)]²
[x(2x-1)]²-7x(2x-1)-144 = 0
Let u = x(2x-1)
u² = [x(2x-1)]²
u² - 7u - 144 = 0
(u - 16)(u + 9) = 0
u - 16 = 0; u + 9 = 0
u = 16; u = -9
Since u = x(2x-1)
x(2x-1) = 16; x(2x-1) = 9
2x² - x = 16; 2x² - x = 9
2x²-x-16 = 0; 2x²-x-9 = 0
x = ; x = ;
x = ; x =
x = ; x =
x = ; x =
Edwin