Answer:
x = 5
Step-by-step explanation:
Given
f(x) = - 3x + 21 and f(x) = 6, then equating gives
- 3x + 21 = 6 ( subtract 21 from both sides )
- 3x = - 15 ( divide both sides by - 3 )
x = 5
This expression is a generic quadratic expression, so the first thing we need to look at is the last term (-40). Is it negative or positive? What are the factors of it? If the last term is negative, we know that one binomial is a subtraction while the other binomial is an addition. You may be asking, "an addition or subtraction of WHAT?" A binomial factored out of a quadratic expression would look something like this: (x + ____). The blank would equal a factor of the last term. In this case, a pair of factors that would fit is 8 and 5.
8x5 = 40 and -8 + 5 = -3.
Plug it into the binomial example I provided above and....
(x - 8)(x+5)=40
Voila! You have your factored quadratic expression, hope this helps!
Answer:
m<AOB = 50°
Step-by-step explanation:
<ACB = 25° is an inscribed angle of the circle.
<AOB is a central angle of the circle.
Thus, based on the inscribed angle theorem which states that an inscribed angle is ½ the measure of the central angle, therefore:
m<ACB = ½(m<AOB)
Substitute
25° = ½(m<AOB)
Multiply both sides by 2
2*25 = m<AOB
m<AOB = 50°