Question

I need help with this please. Can someone help me?
If y=5 when x=-3, find x when y=-1
If y=25 when x=15, find y when x=6

Answer 1

Answer:

5. x=0.6 or 3/5 (it's just the fraction and decimal form)

6. y=10

Step-by-step explanation:

5. We are given y=5 and x=-3, so whenever  and need to find x if y=-1

We need to find the "x" for the second proportion

Using this information we can create a ratio or proportion. To understand this better, (usingy=5 and x=-3) we can say that for every 5 of something (y) we have -3 of something (x). We can create a "key" using the proportionality:$\frac{y}{x}$

here is our proportion $\frac{5}{-3} *\frac{-1}{x}$

lets cross multiply first, 5x=-1(-3)  this simplifies to 5x=3, divide 5 from both sides, 5x/5=3/5  and you x=3/5, so this means that x is 3/5 or 0.6 as decimal

6. Lets set up our "key" again $\frac{y}{x}$,

our ratio is for every 25 something (y) we have 15 something(x) or 25/15 or 25:15

$\frac{25}{15} *\frac{y}{6}$   this is our proportion, lets cross multiply to solve for "y"

25*6=15y this simplifies to 150=15y

lets divide both sides by 15, 150/15-15y/15  and we get our final answer

10=y so our why for this is 10

Answer 2

Answer:

6. $\displaystyle 10 = y$

5. $\displaystyle \frac{3}{5} = x$

Step-by-step explanation:

You are simply dealing with direct proportional relationships:

$\displaystyle \frac{y}{6} = \frac{25}{15}; 10 = y$

These are considered equivalent improper fractions. When simplified, you get $\displaystyle 1\frac{2}{3}.$

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$\displaystyle \frac{-1}{x} = \frac{5}{-3}; \frac{3}{5} = x$

If you look closely, you can tell that there is a 1 being used here, and that you need to divide it by the multiplicative inverse of $\displaystyle \frac{5}{3},$which is $\displaystyle \frac{3}{5},$and sinse both terms are negative integers, you leave the result as is.

I am joyous to assist you at any time.