Question

how do you solve this mathematical question 2×=-20 ?

Answer 1

Follow these steps:

• First, have the equation set up in your preference (I prefer -20 = 2x)
• Then, get the variable (x) by itself by divide both sides by 2
• Once you do that, you'll be left with this: -10 = x

Hope this helps!

Answer 2

If a > 0, then a ˣ > 0 for all real number

$a^x > 0,\ a > 0\ \wedge\ x\in\mathbb{R}$

Therefore 2ˣ = -20 has not solution (x ∈ ∅).

If in the question is positive 20, then:

$2^x=20\ \ \ \ \ |\log_2\\\\\log_22^x=\log_220\\\\x\log_22=\log_2(4\cdot5)\\\\x=\log_24+\log_25\\\\x=\log_2^2+\log_25\\\\x=2\log_22+\log_25\\\\\boxed{x=2+\log_25}$

Used:

$\log_ab^n=n\log_ab\\\\\log_aa=1\\\\\log_a(b\cdot c)=\log_ab+\log_ac$