How do you solve sqrt((5y)/6)-10=45y610=4 and check your solution?

2 Answers
May 31, 2017

See a solution process below:

Explanation:

First, add color(red)(10)10 to each side of the equation to isolate the radical while keeping the equation balanced:

sqrt((5y)/6) - 10 + color(red)(10) = 4 + color(red)(10)5y610+10=4+10

sqrt((5y)/6) - 0 = 145y60=14

sqrt((5y)/6) = 145y6=14

Next, square each side of the equation to eliminate the radical while keeping the equation balanced:

(sqrt((5y)/6))^2 = 14^2(5y6)2=142

(5y)/6 = 1965y6=196

Now, multiply each side of the equation by color(red)(6)/color(blue)(5)65 to solve for yy while keeping the equation balanced:

color(red)(6)/color(blue)(5) xx (5y)/6 = color(red)(6)/color(blue)(5) xx 19665×5y6=65×196

cancel(color(red)(6))/cancel(color(blue)(5)) xx (color(blue)(cancel(color(black)(5)))y)/color(red)(cancel(color(black)(6))) = 1176/5

y = 1176/5

To check the solution we need to substitute color(red)(1176/5) for color(red)(y), calculate each side of the equation and ensure the two results are equal:

sqrt((5color(red)(y))/6) - 10 = 4 becomes:

sqrt((5 xx color(red)(1176/5))/6) - 10 = 4

sqrt((color(red)(cancel(color(black)(5))) xx color(red)(1176/color(black)(cancel(color(red)(5)))))/6) - 10 = 4

sqrt(1176/6) - 10 = 4

+-sqrt(196) - 10 = 4

+-14 - 10 = 4

4 = 4 or -24 = 4

The -14 result of the square root is extraneous.

Therefore, 4 = 4 and the solution is shown to be correct.

May 31, 2017

y = 235.2

Explanation:

sqrt((5y)/6) - 10 = 4

sqrt((5y)/6) = 4 + 10

sqrt((5y)/6) = 14

(5y)/6 = 14^2

(5y)/6 = 196

5y = 196 xx 6

5y = 1176

y = 1176 ÷ 5

color(blue)(y = 235.2

We can now substitute y for 235.2 to prove our answer.

sqrt((5y)/6) - 10 = 4

sqrt((5 xx 235.2)/6) - 10 = 4

sqrt(1176/6) - 10 = 4

sqrt(196) - 10 = 4

14 - 10 = 4