16x² - 49
= (4x)² - 7²
Identity =》 a² - b² = (a + b) (a - b)
(4x)² - 7²
= (4x + 7) (4x - 7) [3rd option]
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Hope it helps ⚜
Answer:
the number of single room is 27 and the number of double room is 53
Step-by-step explanation:
Let x is the number of single room
Let y is the number of double room
We know that:
x + y = 80 <=> x = 80 -y (1)
80x +90y= 6930 (2)
Substitute (1) in (2) we have:
80 (80 - y) + 90y = 6930
<=> 6400 - 80y +90y = 6930
<=> y = 53
> x = 80 - 53 = 27
the number of single room is 27 and the number of double room is 53