The product of two positive numbers is 750. The first number is 5 less than the second number. The equation x(x – 5) = 750 can be used to find x, the value of the greater number. What is the value of the greater number? 15 25 30 50

Respuesta :

Answer:

  30

Step-by-step explanation:

You can try the answer choices to see what works.

  15·10 ≠ 750

  25·20 ≠ 750

  30·25 = 750 . . . . the larger number is 30

  50·45 ≠ 750

Answer:

The value of the greater number is 30.

Step-by-step explanation:

We need to find the values of x that satisfy the equation :

[tex]x(x-5)=750[/tex]

Working with the equation ⇒

[tex]x(x-5)=750[/tex]

[tex]x^{2}-5x=750[/tex]

[tex]x^{2}-5x-750=0[/tex]

Given an equation with the form

[tex]ax^{2}+bx+c=0[/tex]

We can use the quadratic equation to find the values of x

[tex]x1=\frac{-b+\sqrt{b^{2}-4ac}}{2a}[/tex] and

[tex]x2=\frac{-b-\sqrt{b^{2}-4ac}}{2a}[/tex]

With [tex]a=1\\b=-5\\c=-750[/tex] we replace in the equations of x1 and x2 ⇒

[tex]x1=\frac{-(-5)+\sqrt{(-5)^{2}-4.(1).(-750)}}{2.(1)}=30[/tex]

[tex]x1=30[/tex] is a solution of the equation [tex]x^{2}-5x-750=0[/tex]

Now for x2 ⇒

[tex]x2=\frac{-(-5)-\sqrt{(-5)^{2}-4.(1).(-750)}}{2.(1)}=-25[/tex]

[tex]x2=-25[/tex] is a solution of the equation [tex]x^{2}-5x-750=0[/tex]

Given that both numbers are positive ⇒

[tex]x>0[/tex] and [tex](x-5)>0\\x>5[/tex]

Therefore, x2 is not a possible value for the greater number

The greater number is [tex]x1=30[/tex]