So firstly, square root 9a^2 and 49: 
Next, combine like terms, and your answer will be 
, or the third option.
3 times 7= 21 times three =63
The solution of the equation x2+7x is 0, -7 using the quadratic formula.
Step-by-step explanation:
x2 + 7x = 0
-b ± √
b2 - 4(ac)/ 2a
substitution,
a = 1, b = 7, c = 0
= -7 ± √(7)2 - 4(1 x 0) / 2 x 1
= - 7
± 7 / 2
x = 0 , -7
Company a = 22 + 0.07m
company b = 8 + 0.12m
We are looking for the time when the prices are equal. i.e. the price of company a = the price of company b
company a = company b
22 + 0.07m = 8 + 0.12m
22 - 8 = 0.12m - 0.07m
14 = 0.05m
m = 14/0.05
m = 280
Therefore, the two companies will cost the same if you talk for 280 minutes
