Which equation models a line that is perpendicular to y = x - 1 and goes through the point (5,4)

y = - x + 9

Step-by-step explanation:

Because the line is perpendicular, the slope with be the opposite reciprocal. So, if the slope is 1 as in the equation y = x - 1, the opposite reciprocal is -1.

So the equation that is perpendicular will look like this so far:

y = -x + b   (b represents our y-intercept that we have not found yet)

Now we will find the y-intercept. We can find it by substituting the coordinates (5,4) as x and y into the equation right above ^^.

So,  4 = -(5) +b     or     4 = -5 + b

Add 5 to both sides to isolate b on the right side. b = 9

Therefore, the y-intercept is 9.

Now we have found everything we need for the equation, which is

y = - x + 9

.bjbjk.b,j.l.

step-by-step explanation:

let x and 400 - x be the two numbers.  

==> 0.80x + 0.85(400 - x) = 400 - 68 from the statement of the problem.  

< ==> 0.80x + 0.85(400 - x) = 400 - 68  

==> 340 - 0.05x = 332  

< ==> -0.05x = -8 ==> x = 160, the first number ==> 400 - x = 240, the second number.