If shown, AB

and

CD

are straight lines. Find x in each case.
WILL MARK BRAINLISIT

x=60

Step-by-step explanation:

here DOB and AOC are vertically opposite angles and the values of them are equal. so lets take the two angles as y.

x+DOB is 90(because EOA is 90 and the sum of angles in a straight line is 180), DOB is y and can write a equation as x+y=90

and 30+2x+y = 180 ,

2x+y=150, (180-30)

then two equations can be made.

x+y=90

2x+y=150

simplifying these two simultaneous equations

can get x as 60. and 2x is 120.

10a^3+277a^2-132a-792

step-by-step explanation:

(2a+11)(5a-12)(foil)

=10a^2-24a+55a-132 =10a^2+31a-132

(10a^2+31a-132)(a+6)

=10a^3+60a^2+31a^2+186a^2-132a-792 =10a^3+277a^2-132a-792

i hope this is what you are looking for : )

, and

for

step-by-step explanation:

we can analyze the pattern at which the terms increase. let us denote , , , so that we can call

note the following:

the pattern: to get the next term value, we just add the next term number (e.g. 1st, 2nd, to the previous term value (term values are the given numbers in the question, 1, 3, 6, 10, 15,

from , to get to , we add

from , to get to , we add

etc.

we need to form a recursive formula, a formula that has the next term as a function of the previous term. so a possible recursive formula can be

, and for