Answer:
10
Step-by-step explanation:
using HYPOTHENUS theorem
8^2 + 6^2 = x^2
64 + 36= 100
√100=10
A line parallel to the y-axis that passes through (77,88) is x = 77. There is no slope-intercept form of this equation if our coordinate system is based upon a horizontal x-axis and a vertical y-axis.
I’m not 100% sure but i think:
u can multiply 3 on both sides
3x+12=6
subtract 12 from both sides
3x=-6
therefore
x=-2
hope that helps
let's recall that perpendicular lines have negative reciprocal slopes, so say for a line with a slope of a/b

a perpendicular one will be -b/a.
what does that mean? well, that the lines are perpendicular of course, they meet at a 90° angle, and two straight lines meeting at 90° can only meet once.
since a solution to a system of equations is where the graph meet, and these two meet perpendicularly once, then that means only one solution.