Answer:
a) eight and seven ninths minus three and four sixths
Step-by-step explanation:
The required result is 
a)

b)

c)

d)

What’s the question though lol
Answer:
x=[15:-5:-25]'
Step-by-step explanation:
In order to create a vector you need to use this command:
x = [j:i:k]'
This creates a regularly-spaced vector x using i as the increment between elements. j is the initial value and k is the final value. Besides you need to add the character ' at the end in order to convert the arrow vector in a column vector
Answer:
20
Step-by-step explanation:
The two given and marked angles add up to 90.
A = x
B = 3x + 10
A + B = 90 Substitute for A and B. A and B are just letters I gave things.
x + 3x + 10 = 90 Combine the left
4x + 10 = 90 Subtract 10 from both sides.
4x +10-10 = 90-10 Combine
4x = 80 Divide by 4
4x/4=80/4
x = 20