Is the ratio 5:6 equivalent to 3:4

No!

Step-by-step explanation:

This question is essentially asking if =

Well we can easily tell that it doesn't, but if we want to check, we can do cross multiplication.

So we are trying to find out if 5(4) = 3(6).

5(4) = 20 and 3(6) = 18.

so

They are not equal!

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15