Respuesta :

Answer:

Fourth option: x=1±√47

Step-by-step explanation:

This is a quadratic equation, then we must equal to zero: Subtracting both sides of the equation x², 5x, and 39:

[tex]2x^{2}+3x-7-x^{2}-5x-39=x^{2}+5x+39-x^{2}-5x-39[/tex]

Subtracting like terms:

[tex]x^{2}-2x-46=0[/tex]

Applying the quadratic formula:

[tex]ax^{2}+bx+c=0; a=1, b=-2, c=-46[/tex]

[tex]x=\frac{-b+-\sqrt{b^{2}-4ac}}{2a}\\ x=\frac{-(-2)+-\sqrt{(-2)^{2}-4(1)(-46)}}{2(1)}\\ x=\frac{2+-\sqrt{4+184}}{2}\\ x=\frac{2+-\sqrt{188}}{2}\\ x=\frac{2+-\sqrt{4(47)}}{2}\\ x=\frac{2+-\sqrt{4}\sqrt{47}}{2}\\ x=\frac{2+-2\sqrt{47}}{2}\\ x=\frac{2}{2}+- \frac{2\sqrt{47}}{2}\\ x=1+-\sqrt{47}[/tex]


zainebamir540

Answer:

Choice d is correct answer.

Step-by-step explanation:

Given equation is:

2x² + 3x - 7 = x² + 5x + 39

Move all the terms of all equation using subtraction,we get

2x² + 3x - 7 - x² - 5x - 39 = 0

x² - 2x - 46 = 0 is quardatic equation.

ax²+bx+c = 0 is general quadratic equation.

x = ( -b±√b²-4ac) / 2a is qudratic formula.

comparing quadratic equation with general quadratic equation, we get

a = 1 , b = -2 and c = -46

putting above values in quadratic formula, we get

x = ( - (-2)±√(-2)²-4(1)(-46) ) / 2(1)

x = ( 2 ±√4+184) / 2

x = (2±√188) / 2

x = ( 2±√4×47) / 2

x = (2±2√47 ) / 2

x = 2( 1±√47) /2

x = 1±√47 is the solution of given equation.


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