Question

if x-y=80 and 3/5=y/x <--(as a fraction), what is the value of x? will give 45 points, and brainliest for the right answer

Answer 1

Answer:

• (200, 120)

Step-by-step explanation:

Given system

• x - y = 80
• 3/5 = y/x

Solve it by substitution

• y = 3/5(x)
• y = x - 80

Find the value of x

• 3/5(x) = x - 80
• x - 3/5(x) = 80
• 2/5(x) = 80
• x = 80*5/2
• x = 200

Find the value of y

• y = 3/5(200)
• y = 120

Answer 2

Answer:

x = 200

Step-by-step explanation:

Given system of equations:

$\begin{cases}x-y=80\\\\\dfrac{3}{5}=\dfrac{y}{x} \end{cases}$

Rearrange the second equation to make y the subject by multiplying both sides by x:

$\implies \dfrac{3}{5} \cdot x=\dfrac{y}{x} \cdot x$

$\implies y=\dfrac{3}{5}x$

Substitute this into the first equation and solve for x:

$\implies x-\left(\dfrac{3}{5}x\right)=80$

$\implies \dfrac{2}{5}x=80$

$\implies \dfrac{2}{5}x \cdot 5=80 \cdot 5$

$\implies 2x=400$

$\implies \dfrac{2x}{2}=\dfrac{400}{2}$

$\implies x=200$

Therefore, the value of x is 200.

If you want to find the value of y, simply substitute the found value of x into the first equation and solve for y:

$\implies 200-y=80$

$\implies 200-y+y=80+y$

$\implies 200=y+80$

$\implies 200-80=y+80-80$

$\implies 120=y$

$\implies y=120$