We'll use Cramer's rule for 2 equations:
ax + by = e
cx + dy = f
5x -3y = 18 a=5 b=-3 e=18
2x + 7y = -1 c=2 d=7 f=-1
denominator determinant (dn) = (a * d) - (c * b) = 5 * 7 - (2 * -3) = 41
x = [(e * d) - (f * b)] / dn
[18 * 7 - (-1 * -3)] / 41 =
123 / 41 = 3
y = [(a * f) - (c * e)] / dn
= (5 * -1) -(2 * 18) / 41 =
-41 / 41 = -1
Source:
1728.com/cramer.htm
Answer:
5y = -2x + 31
Step-by-step explanation:
Given equation:
y = 
Coordinate = (-7,9)
Unknown:
Equation of the line perpendicular = ?
Solution:
The slope - intercept format of a line is given as;
y = mx + c
where y and x are the coordinates
m is the slope
c is the y-intercept
y = 
From the given equation; slope is 
A line perpendicular will have a slope that is negative and the inverse of this;
slope of perpendicular line = 
Since y= 9 and x = -7;
So;
9 =
+ C
9 =
+ C
C = 9 -
= 
Now,
y =
x + 
mulitply through by 5;
5y = -2x + 31
Answer:
48
Step-by-step explanation:
100/50 = 2
This means each question was worth 2%
96% / 2% = 48
She got 48 questions right