Write the equation of a line through the points (−7,14) and (−21,28) in slope-intercept form

y= -x + 7

Solution:

Step 1 : find the slope using the equation using the pair of coordinates that are given i.e A (−7,14)  B (−21,28) ( name them A and B respectively so they can be easily named as x1, y1 and x2,y2 respectively)

m = y2-y1/x2-x1

m = 28-14 / -21 -( -7)

m =  14 / -14

m = -1

Step 2 : Find the y intercept using the line of equation (use and one of the given coordinates either A or B)

Using A ( -7, 14)

y= mx+ b

14 = (-1)(-7) + b

14= 7 + b

14-7 = b

7 =b

So,

y=mx+b

Insert m and b

y= -x + 7

f(x) = - 2/3x + 5; f(5/2)

substitute 5/2 in for x:

f(5/2) = -2/3(5/2) + 5

simplify the right side:

f(5/2) = -5/3 + 5

f(5/2) = 10/3

answer:

f(5/2) = 10/3

i hope this you!