Solve for t. t – 15.7 = 53.4 * a. 38.7b. 68.1 c. 37.7 d.69.1

The answer is D) 69.1

Solution:
t - 15.7 = 53.4
 + 15.7   +15.7
t = 69.1

Explanation:
In order to solve for t, you first need to get t by itself.  
You get t by itself by adding 15.7 to both sides.
53.4 + 15.7 = 69.1
t = 69.1

Ithink the answer is d.

x^2 + 81

we can factor this using difference of square binomials.

rewrite the equation:

x^2 - (-81)

factor:

(a^2 - b^2) = (√a^2 + √b^2)(√a^2 - √b^2)

(x^2 - (-81) = (x + √-81)(x - √-81)

we can remove the - from under the radical by multiplying it by i.

(x^2 - (-81) = (x + i√81)(x - i√81)

(x^2 - (-81) = (x + 9i)(x - 9i)

(x + 9i)(x - 9i)

we can check our answer by using foil:

x^2 - 9ix + 9ix - 81i^2

x^2 - 81^2

i^2 = -1

x^2 + 81