Answer:
19.1 feet
Step-by-step explanation:
Length of the ladder = 20 feet
Distance from the ladder to the wall = 6 feet
Height of the ladder on the wall = x
x² + 6² = 20²
x² = 20² - 6²
x² = 364
x = 19.1 feet (Rounded to nearest tenth)
Correct! lines that have undefined slopes are always parallel to the y-axis as the change in x is 0. A gradient is calculated by the change in y divided by the change in x and anything divided by 0 is referred to as undefined.

(calculation for a gradient)
Hope that helps sorry if its a bit confusing :)
(3w + 9) + (6w + 7) + (8w - 4) =
= 3w + 9 + 6w + 7 + 8w - 4 =
= 3w + 6w + 8w + 9 + 7 - 4 = <u>1</u><u>7</u><u>w</u><u> </u><u>+</u><u> </u><u>1</u><u>2</u>