Complete the statement of each of these rules: a (+)×(?)=(+)
b (-)×(+)=?
c (?)×(-)=?

a) (+) × (?) = (+)

(?) = (+)

b) (-) × (+) = ?

? = (-)

c) (?) × (-) = ?

? is undefined

Step-by-step explanation:

a) (+) × (?) = (+)

From the given equation in the question, by dividing both side of the equation by (+), we have;

((+) × (?))/(+) = (+)/(+)

(?) = (+)/(+) = (+)

Therefore, we have;

(+) × (+) = (+)

(?) = (+)

b) (-) × (+) = ?

From the given equation in the question we apply the operation rules as follows;

(-) × (-) = (+)

(-) × (+) = (-)

Therefore;

(-) × (+) = ? = (-)

? = (-)

c) (?) × (-) = ?

From the rules of multiplication, we have;

(-) × (-) = (+)

(+) × (-) = (-)

Therefore, when (?) = (-), ? = +, from which we have;

(?) ≠ ?, which is an error

Similarly, when (?) = (+), ? = -, therefore, (?) and ?, always changes sign

Therefore, the equation, (?) × (-) = ?, is undefined.

he spend 5.1 minutes chatting with his friends

step-by-step explanation:

2/5+1/2=9/10

6/1-9/10=5 1/10

t = 3

step-by-step explanation:

put t = 3 in this expression :

(3²-1)(3²-2)(3² - 3)(3² - 4) = 8×7×6×5 = 56×30 = 1680