Number expression for 84

How do we get a bigger number? Subtracting or dividing will just make it smaller. So we have to multiply. We need it about 4 times bigger (3 x 28 = 84, 4 x 28 .

Step-by-step explanation:

A number can be any number. It can be 4, it can be 56, it can even be 452,890.14. So the number expression for 84, would have to be 84. It's that simple. If there's something I'm missing, (i'm just an 8th grader) tell me please. Otherwise, your a doofus.

ok then what happened.

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