Answer:Although the Quadratic Formula always works as a strategy to solve quadratic equations, for many problems it is not the most efficient method. Sometimes it is faster to factor or complete the square or even just "out-think" the problem. For each equation below, choose the method you think is most efficient to solve the equation and explain your reason. Note that you do not actually need to solve the equation. a. x2+7x−8=0x
2
+7x−8=0, b. (x+2)2=49(x+2)
2
=49, c. 5x2−x−7=05x
2
−x−7=0, d. x2+4x=−1x
2
+4x=−1.
No, 12 rounded to the nearest tenth is 12.0
The expressions of the number of radians can be expressed in the ways below.
<h3>How to write the expressions</h3>
The radius = 1.9 km
The angular speed = 3.1 radians per hour
a. The expression of t from the number of radians
θ = π/2 + 3.1t
<h3>b. Expression from the East</h3>
x = rcosθ
= 1.9cos(π/2 + 3.1t)km
<h3>c. Expression from the north of the center</h3>
= rsinθ
= 1.9sin((π/2 + 3.1t)km
Read more on angular speed here:
brainly.com/question/6860269
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One and a half gallons. (1.5 gallons)