Step-by-step explanation:

Let,
digital cameras be "x"
video cameras be "y"
Now,
According to the question,
5x + 3y = $3,213..................................................equation (1)
y = 4x..................................................................equation (2)
Taking equation (1)
5x + 3y = $3,213
Substituting the value of "y" from equation (2), we get,
5x + 3(4x) = $3,213
5x + 12x = $3,213
17x = $3,213
x = $3,213 / 17
x = $189
Taking equation (2)
y = 4x
Substituting the value of "x", we get,
y = 4 ($189)
y = $756
Now,
John buys a digital and a video camera. So, it costs him ($189 + $756) = $945
F(x)=3 domain: negative infinity, positive infinity range: 3
g(x)=x+7 domain: - infinity, + infinity range: - infinity, + infinity
You can factor out 36*5=180 and 27*4=108 and find that they have 36 as greatest common divisor. The x and y factors have xy as the best you can divide by. So the factor becomes 36xy
36xy(5y²+3) = 36x5y³ + 27x4y