Combine like terms:

1. -21a 16a
a -5a
b 5a
c 37a
d -37a**

2. 5 (x 10) x

a 6x 15 **
b 5x 15
c 6x 50
d 4x - 50

Pls! does anybody know a shortcut for answering these types of questions in the future?

One astronomical unit (1 au) is about 1.496 alt tag missing. kilometers. if you wrote this number of kilometers in regular decimal notation (for example, 528 and 3,459 are written in regular decimal notation), how many zeros would your number have?

What is the value of x? enter your answer in the box.