Step - 1: Calculate 20% of 840.
Step - 2: Subtract from 840.
N + 12 = 31
N = 31 - 12
N = 19
Answer:
y = 3/2 x - 11
Step-by-step explanation:
y = -2/3 x + 5; slope = -2/3
Perpendicular line, slope is reciprocal and opposite so slope of the line that is perpendicular to the y = -2/3 x + 5 is 3/2
Passes through (8,1)
Equation
y -1 = 3/2 (x - 8)
y - 1 = 3/2 x - 12
y = 3/2 x - 11
If we draw a rhombus OABC on a coordinate grid with one vertex at the point O (0,0)
and let its height be 1 then (using the Pythagoras theorem) the coordinates of the 4 points will be as follows:-
O = (0,0) , A = (1, 1), B = (sqrt2+ 1 , 1) , C = (sqrt2, 0)
Slope of the diagonal OB = 1 / (sqrt2 + 1)
Slope of the other diagonal AC = - 1 / (sqrt2 - 1)
Product of the slopes = - 1 / ( sqrt2 + 1)(sqrt2 - 1) = -1 / 1 = -1
This proves that the diagonals are perpendicular.
