X=8 y=20 find y when x=42

In this problem, we need to use the concept of proportions. Proportion says that two ratios (or fractions) are equal. So, we have two numbers, namely:

So, the given proportion is:

That is, x-out-of-y is equal to 2-out-of-5

On the other hand, we know that , so by using the previous proportion we have:

Answer

y= 105

Explanation

X=8

Y=20

So,

x/y = 8/20

      = 2/5

x=(2/5)y

y= (5/2)x

When x=42

y=(5/2)×42

   =105

(0,-3) see attached graph

step-by-step explanation:

a. to solve the system, graph the two equations.

x = y+3 becomes y=x-3 has m=1/1 and b=-3. start at (0,-3) on the y-axis and plot a point. then move up 1 unit and 1 unit to the right. plot a point and connect.

y=-4x+3 has m =-4/1 and b=-3. start at (0,-3) on the y-axis and plot a point. then move down four units and to the right 1 unit. plot a point and connect.

the solution is the point (x,y) where the two lines intersect. by the graph below it is (0,-3).

b. to solve by substitution, substitute y = -4x-3 into x= y+3

x= (-4x-3) +3

x=-4x

5x=0

x=0

now substitute x = 0 back in to find y.

y= -4(0)-3

y=0-3

y=-3

solution is (0,-3)

c. use elimination by adding the equations together.

x-y=3

4x+y=-3

5x=0

x=0

then substitute into one equation to find y.

y=-4(0)-3

y=-3