Answer:
Move all terms to the left side of the equation and simplify.
3x²−12x−21=0
Use the quadratic formula to find the solutions.
(−b±√b²−4(ac))/2a
Substitute the values a=3, b=−12, and c=−21 into the quadratic formula and solve for x.
(12±√(−12)²−4⋅(3⋅−21)0/2⋅3 Simplify => x=2±√11
The result can be shown in multiple forms.
Exact Form: x=2±√11
Decimal Form: x=5.31662479…,−1.31662479…
Step-by-step explanation:
Answer:
C
Step-by-step explanation:
The difference formula for cosine is
cos(x - y) = cosxcosy + sinxsiny
Consider
cos75 = cos(120 - 45)°, then
cos(120 - 45)°
= cos120°cos45° + sin120°sin45° → C
Okay uh
x = 2y + 9
14x + 2y = - 54
14x + 2y = - 54
14(2y + 9) + 2y = - 54
28y + 126 + 2y = -54
30y + 126 = -54
- 126 -126
30y = -180
30y/30 = -180/30
y = -6
x = 2y + 9
x = 2(-6) + 9
x = -12 + 9
x = -3
(x, y) = (-3, -6)