Answer:
no. see below
Step-by-step explanation:
This much of Josh's working is correct:
x^2-6x=7
x^2-6x+9=7+9
(x-3)^2=16
At this point Josh apparently overlooked the fact that he needed to take the square root of both sides of the equation. Had he done that, he would have ...
x -3 = ±4
x = 3+4 . . . or . . . 3 -4
x = 7 or -1
_____
Josh reported values of x that would match ...
x -3 = ±16
He <em>violated the equal sign</em> by taking the square root on the left, and multiplying by ±1 on the right. Doing different operations on the two sides of the equation will mean the value of x is changed to something other than what you're looking for.
Answer:
31.5
Step-by-step explanation:
.......
Answer:
4
Step-by-step explanation:
Answer:
-24.8 m/s
Step-by-step explanation:
Given:
y₀ = 60 m
y = 40 m
v₀ = 15 m/s
a = -9.8 m/s²
Find: v
There are three constant acceleration equations we can use:
y = y₀ + v₀ t + ½ at²
v = at + v₀
v² = v₀² + 2a(y − y₀)
We aren't given the time, so we need to use the third equation, which is independent of time:
v² = v₀² + 2a(y − y₀)
Plug in the values:
v² = (15 m/s)² + 2(-9.8 m/s²) (40 m − 60 m)
v² = 617 m²/s²
v ≈ ±24.8 m/s
Since the coin is on the way down, the velocity is negative. So v = -24.8 m/s.
