Answer:

Step-by-step explanation:
Isolate the variable by dividing each side by factors that don't contain the variable.
The kinetic energy transfers from the moving ball to the non-moving ball.
the 2 angles are congruent so...
x+40=3x set the 2 equations equal to each other
40=2x subtract x from both sides
20=x divide by 2
x=20 is the final answer
Have a blessed day!
Answer:
x² + 4x + 20 = 12x - 5
x² + 4x - 12x + 20 + 5 = 0
x² - 8x + 25 = 0
Δ = √b² - 4ac
= √(-8)² - 4×1×25
= √64-100
= √(-36)
x ∉ R