Answer:
A.
Step-by-step explanation:
Answer: x = 4 and x = -3/2
Procedure:
1) Given: 2x^2 - 5x - 12 = 0
2) Multiply both sides by : 2(2x^2) - 2(5x) - 2(12) = 0
3) Rearrange: (2x)^2 -5(2x) - 24 = 0
4) Notice that the common factor is (2x)
5) Set the parenthesis with the common factor inside:
(2x ) (2x ) =0
6) The first sign is the same sign of the second term of the trinomial, which is negative, the second sign is the product of the signs of the second and the third terms of the polynomial, which is (-)*(-) = + (positive)
(2x - )(2x + ) = 0
7) find two numbers that sum up - 5x and its product is -24.
- 8 + 3 = - 5
(-8)(+3) = -24
=> the numbers in the factors are -8 and +3
(2x - 8) (2x + 3) = 0
That is the factored equation. Now you can solve
8) a) 2x - 8 = 0 => 2x = 8 => x = 8/2 => x = 4
b) 2x + 3 = 0 => 2x = - 3 => x = - 3/2
Answer: the two solutions are x = 4 and x = -3/2
Answer:
a) 150 plates
b) 30 plates
c) 180 plates
Step-by-step explanation:
Given that:
She bought twelve (12) packages of plates for the party in which each package contains 15 plates.
Out of the 12 packages;
10packages are small plates & 2 packages are large plates.
a) The number of small plates she bought = 10 × 15 = 150 plates
b) The number of large plates she bought = 2 × 15 = 30 plates
c) The total number of plates she bought all together is:
= number of small plates bought + = number of large plates bought
= (150 +30) plates
The total number of plates she bought all together = 180 plates
we have that
![2sin^{2} x-5sin x-3=0](https://tex.z-dn.net/?f=%202sin%5E%7B2%7D%20x-5sin%20x-3%3D0%20)
I. Rewrite the equation by substituting the expression u in for sin x.
![2u^{2} -5u-3=0](https://tex.z-dn.net/?f=%202u%5E%7B2%7D%20-5u-3%3D0%20)
II. Factor the quadratic expression. Rewrite the equation with factors instead of the original polynomial.
is equal to
using a graph calculator-----> see the attached figure
![(u-3)*(2u+1)=0](https://tex.z-dn.net/?f=%20%28u-3%29%2A%282u%2B1%29%3D0%20)
III. Use the zero product property to solve the quadratic equation.
![(u-3)*(2u+1)=0](https://tex.z-dn.net/?f=%20%28u-3%29%2A%282u%2B1%29%3D0%20)
(u-3)=0--------------> u=3
(2u+1)=0-------- 2u=-1------> u=-1/2-----> u=-0.5
IV. Rewrite your solutions to Part III by replacing u with sin x.
sin x=3--------> is not the solution (sin x can not be greater than 1)
sin x=-0.50------>is the solution
V. Solve the remaining equations for x, giving all solutions to the equation.
sin x=-0.50
if the sine is negative
then
x belong to the III or IV quadrant
we know that
sin 30°=0.50
so
the solution for the III quadrant is
x=180°+30°-------> x=210°
the solution for the IV quadrant is
x=360°-30°------> x=330°
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