Question

A new office building in town has x2 + 4 floors. Each floor is 3x2 – 5 feet high. Which expression shows the total height of this office building?

Answer 1

Answer: $3x^{4}+7x^{2}-20$

Step-by-step explanation:

1. You know that:

- The number of floors is given by the expression $x^{2}+4$.

- The height of each floor is given by the expression $3x^{2}-5$.

2. Then, to find the expression that shows the total height of the office building, you must multiply the height of each floor by the number of floors. Therefore, you obtain the following result:

$(x^{2}+4)(3x^{2}-5)=3x^{4}-5x^{2}+12x^{2}-20=3x^{4}+7x^{2}-20$