(2x+1)(x-5)-(x+3)(x-2)=-17?

Question

I ended up with 10 & -2 for my answers when I tried this equation. Anybody get anything else? I think I may have simplified it a bit too much when I was going through it.

Answer 1

For x over the set of real numbers:

(2x + 1)(x - 5) - (x + 3)(x - 2) = -17

(2x² - 9x - 5) - (x² + x - 6) = -17

x² - 10x + 1 = -17

x² - 10x = -18

x² -10x +25 = -18 +25

(x - 5)² = 7

|x - 5| = √7

x - 5 = ±√7

x = 5 ± √7


{5 + √7, 5 - √7}

Answer 2

Solve,

(2x + 1)(x - 5) - (x + 3)(x - 2)= -17

(2x^2 - 9x - 5) - (x^2 + x - 6) = -17

2x^2 - 9x - 5 - x^2 - x + 6 = -17

x^2 - 10x + 18 = 0

Use general formula:

x = [ -b +/- sqrt(b^2 - 4ac)] / 2a

where:

a = 1

b = -10

c = 18

Substitute in the values,

x = [10 +/- sqrt(100 - 4(1)(18))] / (2(1))

x = [10 +/- sqrt(28)] / 2


x = 5 + sqrt(7) or

x = 5 - sqrt(7)


Use WinXP Calculator gives:

x = 7.6457513110645905905016157536393

x = 2.3542486889354094094983842463607

Answer 3

(2x+1)(x-5)-(x+3)(x-2)=-17
(2x^2 - 10x + x - 5) - (x^2 - 2x + 3x -6) = -17
(2x^2 - 9x - 5) - (x^2 + x -6) = -17
x^2 - 10x +1 = -17
x^2 - 10x + 18 = 0
Use the quadratic formula to solve it since it is not factorisable.

Answer 4

It's been awhile since I've done this stuff so take it with a grain of salt....

Using FOIL (First, Outer, Inner, Last)
(2x^2+2x-5+x-10)-(x^2-2x+3x-6) = -1
(2x^2+3x-10)-(x^2+x-6) = -1
x^2+2x-16 = -1
x^2+2x = 15
x=3 (3^2 +2*3) = (9+6) = 15

Answer 5

= 2x^2 - 9x - 5 - x^2 - x + 6 = -17
x^2 - 10x + 18 = 0

Answer 6

(2x+1)(x-5)-(x+3)(x-2)=-17

on expansion gives:

(2x^2 - 9x - 5) - (x^2 + x -6) = -17

collecting terms;

x^2 - 10x - 11 = -17

therefore

x^2 - 10x + 6 = 0

Solve using x = (-b +/- sqrt(b^2 - 4ac))/2a

= (10 +/- 8.72)/2 ie
9.36 or 0.64

check by back substitution, i find agrees pretty well.

Answer 7

(2x+1)(x-5)-(x+3)(x-2)=-17
2x^2-10x+x-5-x^2+2x-3x+6=-17
x^2-10x+18=0
I've got this.Dont know what 2 do next.Check whether the question is right or wrong.

Answer 8

If you plug in your two answers, neither of them gives a correct resolution

Answer 9

I got x = 2.354, 7.646