contestada

Myles and Darrell are brothers and myles is older. When you square Darrell's age and multiply by 2 and subtract from the square of Myles age the result is 6times the difference between their ages. When add Myles and Darrell's age you get 5times the difference between their ages. How old is Darrell and how old is Myles.

Respuesta :

Answer:

Darrell is 12 years old while Darrell is 18 years old

Step-by-step explanation:

Let Myles age be m and Darrell age be d

Single Myles is older, m > d

Square Darrell’s age and multiply by 2; d^2 * 2 = 2d^2

Subtract from the square of Myles age

m^2 - 2d^2

Result is 6 times the difference between their ages;

m^2 - 2d^2 = 6(m-d) •••••••••••(i)

When add Myles and Darrell age

m+ d

you get 5 times the difference between their ages 5(m-d)

m + d = 5(m-d)

m + d = 5m - 5d

5m - m = 5d + d

4m = 6d

m = 6d/4

m = 1.5d or 3/2d ••••••••(ii)

Put ii into i

(3/2d)^2 - 2d^2 = 6(3/2d - d)

9/4d^2 - 2d^2 = 6(1/2)d

Multiply through by 4

9d^2 - 8d^2 = 12d

d^2 = 12d

d^2 - 12d = 0

d(d -12) = 0

d = 0 or d-12 = 0

d = 0 or 12

d = 12 years

The age cannot be zero (if Darrel age is zero, then Myles age will be zero too, this cannot work as their ages are not equal)

So we choose 12 years

Recall ; m = 3/2 d = 3/2 * 12 = 18 years

Otras preguntas