Answer:
{-2,10}
Step-by-step explanation:
x^2 - 8x = 20
Take the coefficient of x
-8
Divide by 2
-8/2 =-4
Square it
(-4)^2 =16
Add this to each side
x^2 - 8x+16 = 20+16
x^2 - 8x+16 = 36
The left hand side becomes( x + (-8/2) )^2
(x - 4)^2 = 36
Take the square root of each side
sqrt((x - 4)^2) =±sqrt( 36)
x-4 = ±6
Add 4 to each side
x-4+4 = 4±6
x = 4±6
x = 4+6 x = 4-6
x = 10 x = -2
Answer:
4
5(2)+5(7)
Step-by-step explanation:
(1) <span>The surface area of the square pyramid = 4 * (area of one face) + area of the base
area of one face = 0.5 * 34.2 * 28.4
area of the base = 34.2 * 34.2
∴ </span>The surface area of the pyramid = 4 * (<span>0.5 * 34.2 * 28.4) + </span><span>34.2 * 34.2
By comparing the last answer with the answer of </span>Vikram, we find that:
He used the wrong expression to represent the area of the base of the pyramid.
=========================================================
(2) The surface area of the rectangular pyramid
= area of two face with the height 36.5 + area of two face with the height 37.8 + area of the base
area of two face with the height 36.5 = 2 * 0.5 * 36.5 * 25.6
area of two face with the height 37.8 = 2 * 0.5 * 37.8 * 16.2
are of the base = 25.6 * 16.2
Total area = (2 * 0.5 * 36.5 * 25.6) + (2 * 0.5 * 37.8 * 16.2) + (25.6 * 16.2)
= (36.5 * 25.6) + (37.8 * 16.2) + (25.6 * 16.2)
note: 2 *0.5 = 1
By comparing the last answer with the answer of Tracy , we find that:
<span>Tracy’s answer will be correct because she made use of the fact that 2 (1/2) = 1 in her expression.
=========================================================
</span>
(3)
the total surface area of this rectangular pyramid =
= area of two face with the height 52 + area of two face with the height 60 + area of the base
area of two face with the height 52 = 2 * 0.5 * 52 * 78 = 4,056 m²
area of two face with the height 60 = 2 * 0.5 * 60 * 50 = 3,000 m²
are of the base = 78 * 50 = 3900 m²
Total area = 4,056 + 3,000 + 3,900 = 10,956 m²
Answer:
56
Step-by-step explanation:
There were 20 people in a bar. 10 people left. Then 4 more people left. 6 people were left
