to find the area of a rectangle is LxW=A
plug in the given numbers you have
L = 7
W = x-8
A = 42
7 * x-8 = 42
7x-56= 42
solve for X
How much part can sally paint in an hour ?
a ÷ 7 = a/7
And what about Steve ?
a ÷ 9 = a/9
Where, a is the total area of the room.
So, let the time taken by both of them to paint the room together be 't'
So,
t(a/7 + a/9) = a
t(9a/63 + 7a/63) = a
t(16a/63) = a
t = 63/16 ≈ 4 hr
6x = n²-16
n²-6x-16=0 -16=-8*2, -6=-8+2
(n-8)(n+2)=0
n-8=0, n+2=0
n=8, n=-2
Negative solution is -2.
