Answer:
∠ ABC ≈ 137.9°
Step-by-step explanation:
Using the Cosine rule in Δ ABC
cos B = 
with a = 89, b = 144, c = 65
cos B =
=
=
, thus
B =
( -
) ≈ 137.9° ( to the nearest tenth )
R = x(A+B)
distribute
R=Ax+Bx
subtract Ax from each side
R-Ax=Bx
divideby x
(R-Ax)/x =B
Choice C
Answer:
x = ±2sqrt(2)
Step-by-step explanation:
x^2 = 8
Take the square root of each side
sqrt(x^2) = ±sqrt(8)
x = ±sqrt(4*2)
We know that sqrt(ab) = sqrt(a)sqrt(b)
x = ±sqrt(4)sqrt(2)
x = ±2sqrt(2)