The area of a rectangle can be expressed by 2x2 – 7x – 4. If the rectangle has an area of 45, find the positive value for x.

7

Step-by-step explanation:

2x^2 - 7x - 4 = 45

2x^2 - 7x - 49 = 0 : subtract 45 from both sides

Quadratic formula:

  x = (7 ± sqrt(7^2 - 4*2*-49) ) / 4

  x = (7 ± sqrt(49 - -392)) / 4

  x = (7 ± sqrt(441)) / 4

  x = (7 ± 21) / 4

  x = (7 + 21) / 4 OR x = (7 - 21) / 4

  x = 28 / 4 OR x = -14 / 4

  x = 7 as it is the only positive answer

5=812a+9+3

step 1: simplify both sides of the equation.

5=812a+9+3

5=(812a)+(9+3)(combine like terms)

5=812a+12

5=812a+12

step 2: flip the equation.

812a+12=5

step 3: subtract 12 from both sides.

812a+12−12=5−12

812a=−7

step 4: divide both sides by 812.

812a /812 = -7/812

a= -1/116

so the answer is

a=   -1/116