Mike and dena are painting a fence. if mike has done 1/3 of the job and dena has done 2/7 of the job, what fraction of the job is left to be finished?

8/21

Step-by-step explanation:

The total job is 1

Mike has done 1/3    and Dena has done 2/7 of the job   We still need to do x of the job to complete it

1/3 + 2/7+ x  = 1

We need to get a common denominator 3*7 = 21

Multiply each side by 21

21(1/3 + 2/7+ x)  = 1*21

21(1/3) + 21*(2/7)+ 21x  = 21

7+ 3*2 +21x =21

7+6+21x = 21

13+21x = 21

Subtract 13 from each side

13-13+21x=21-13

21x = 8

Divide each side by 21

21x/21 = 8/21

x = 8/21

We need to complete 8/21 of the job

y = -2x  + 7

Step-by-step explanation:

When 2 lines are perpendicular, the relationship between their slopes m1 and m2 may be stated as

m1m2 = -1

Given the line

y = 1/2 x + 8

Comparing with the general equation of a line y = mx + c where m is the slope and c is the intercept

m = m1 = 1/2

Hence the slope of the perpendicular line m2

= -1/1/2

= -2

Given that the line passes through the points (1,5)

using the equation

y - y1 = m (x - x1)

y - 5 = -2(x - 1)

y = -2x +2 + 5

y = -2x  + 7