Got you. So we will use the basic formula for the area of a rectangle and insert variable values. (^_^)
Area= Width(Height) ----------- Insert values of width and height [width = (x-1)
, height = (x+9)]
Area= (x-1)(x+9) ) -------------- Then expand if needed?
= x² +8x -9
Answer:
54.3m
Step-by-step explanation:
h = distance above sea level
d = distance he can sea above sea level
d = 3.57h
h = 15.21m
d = ?
d = 3.57 × 15.21
d = 54.2997m approximately 54.3m
The person can see up to a distance of 54.3m
Answer:
x = -
, x = 
Step-by-step explanation:
to find the points of intersection equate the 2 equations , that is
7x - 15 = 10 + 12x - 6x² ( subtract 10 + 12x - 6x² from both sides )
6x² - 5x - 25 = 0 ← factor the quadratic on left side
consider the factors of the product of the coefficient of the x² term and the constant term which sum to give the coefficient of the x- term
product = 6 × - 25 = - 150 and sum = - 5
the factors are - 15 and + 10
use these factors to split the x- term
6x² - 15x + 10x - 25 = 0 ( factor the first/second and third/fourth terms )
3x(2x - 5) + 5(2x - 5) = 0 ← factor out (2x - 5) from each term
(2x - 5)(3x + 5) = 0
equate each factor to zero and solve for x
3x + 5 = 0 ⇒ 3x = - 5 ⇒ x = - 
2x - 5 = 0 ⇒ 2x = 5 ⇒ x = 