Which point lies on the line with point-slope equation y - 3 = 4(x + 7)? A.
(7, 3)

B.
(7, -3)

C.
(-7, -3)

D.
(-7, 3)

D. (-7, 3)

Step-by-step explanation:

The equation given is in point-slope form.

Point-slope form is:

y-y1=m(x-x1)

This is where:

y1 is the y-coordinate of a point it goes through

m is the slope of the line

x1 is the x-coordinate of a point that it goes through

That said, in the given equation:

y1=3

m=4

x1=-7

Note that a point is (x-coordinate, y-coordinate)

Therefore, (-7, 3) is the point that lies on the line.

(b) 240

step-by-step explanation:

first, we use the pythagorean formula using the given side lengths to find x. then we use x to find the side lengths. then we add the side lengths to find the perimeter.

pythagorean theorem formula:

a^2 + b^2 = c^2

(x - 20)^2 + (x - 40)^2 = x^2

x^2 - 40x + 400 + x^2 - 80x + 1600 = x^2

x^2 -120x + 2000 = 0

(x - 100)(x - 20) = 0

x - 100 = 0 or x - 20 = 0

x = 100 or x = 20

we see that the solution x = 20 must be discarded because it will give a negative side length and a side length of 0. the only valid solution is x = 100.

perimeter = sum of the lengths of the sides

perimeter = x + x - 20 + x - 40

perimeter = 3x - 60

replace x with 100.

perimeter = 3(100) - 60

perimeter = 300 - 60

perimeter = 240