3a+7
Step-by-step explanation:
Answer: Telescopes use lenses or mirrors to collect and focus waves from the electromagnetic spectrum, including visible light, allowing us to look at celestial objects. By studying the electromagnetic waves given off by objects such as stars, galaxies, and black holes, astronomers can better understand the universe.
Step-by-step explanation:
Conjugate of 9-5i is 9+5i
product of those two: (9-5i)*(9+5i) =
Answer:
x=3
Explanation:
Let's write an equation for the area of this figure.
This figure can be divided into 2 rectangles, a vertical and horizontal rectangle.
Area of rectangle= length× breadth
Area of vertical rectangle= 6x
Length of horizontal rectangle= (7 -x) cm
Area of horizontal rectangle= x(7-x)
Since total area= 30 cm^2,
6x+ x(7-x)= 30
6x +7x -x^2= 30 (expand)
-x^2 +13x-30= 0 (bring all terms to one side)
x^2 -13x +30= 0 (divide by -1)
(x -10)(x -3)= 0 (factorise)
x -10= 0 or x -3= 0
x= 10 or x= 3
(reject)
We reject x=10 since from the diagram, x cm is less than 6cm.
Answer:
a
Step-by-step explanation:
