Question

The line graphed below has a slope equal to -2. The point (3, 28) lies on

this line as shown. Determine the y-value on this line when the x-value is
equal to 11.

Answer 1

y = 12

Explanation:

We'll use the form of an equation of a straight line of y=mx+b, where m is the slope and b the y-intercept (the value of y when x=0).

We are told the slope, m, is -2.

That leads to: y = -2x + b

y = -2x + b

B, the y-intercept, can be found by using the given point (3,28) in the equation (it falls on the line, so must be a valid solution to the equation. Use the given x and y in the equation and solve for b:

y = -2x + b

28 = -2*(3) + b

28 = -6 + b

b = 34

The equation is y = -2x + 34

Use this to find y when x = 11:

y = -2(11) + 34

y = -22 + 34

y = 12

y is 12 when x is 11

See the attached graph.