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A rectangle has a length of (x+3), width of (x-4) and an area of 120. What is the perimeter of the rectangle?

a. 40
b. 42
c. 46
d. 48

Respuesta :

Answer:

Option C, [tex]46[/tex]

Step-by-step explanation:

Step 1:  Distribute

Formula → [tex]A = l * w[/tex]

[tex]120 = (x+3) * (x-4)[/tex]

[tex]120 = (x*x)+(x*-4)+(3*x)+(3*-4)[/tex]

[tex]120 = x^2 - 4x + 3x - 12[/tex]

Step 2:  Solve for x

[tex]120 - 120 = x^2 - x - 12 - 120[/tex]

[tex]0 = x^2 - x - 132[/tex]

[tex]0 = (x - 12)(x + 11)[/tex]

[tex]x = 12, -11[/tex]

Step 3:  Determine the perimeter of the rectangle

[tex]P = 2(l + w)[/tex]

[tex]P = 2((12 + 3) + (12-4))[/tex]

[tex]P = 2(15 + 8)[/tex]

[tex]P = 2(23)[/tex]

[tex]P = 46[/tex]

Answer:  Option C, [tex]46[/tex]