How do I solve this linear equation?

21+x=30

Cómo se resuelven las ecuaciones químicas?

What is algebraic expression for the difference of 2 and the product of 3 and k

The hypotenuse of a right triangle is 15cm long. One of the triangle's legs is two times the length of the other leg. Find the lengths of the three sides of the triangle. For non-integer answer (s), round your answer (s) to the nearest tenth.

A spinner with 5 equal sections is spun. Then a number cube is rolled. How many outcomes are there for the two events happening one after the other?

What is the measure of Angle R in PQR? Round to the nearest degree. 26 42 45 64

Write the equation in standard form. Then factor the left side of the equation. 3x2 + 19x = 14

Which expression is equivalent to 36x^2-100

My number had 10 digits and its 8 more than 1. Zero is not my digit. My number is what?

What is 18 divided by 10?

Find the area of the given square. 100 feet 60 feet