# Help : Algebra

$$87.75 = R^2 - 7R$$

How to get $$R$$ ?

I tried many times but i didn't get it

The answer is $$13.5$$ but i don't know how to get it

Note by Jason Chrysoprase
2 years, 3 months ago

MarkdownAppears as
*italics* or _italics_ italics
**bold** or __bold__ bold
- bulleted- list
• bulleted
• list
1. numbered2. list
1. numbered
2. list
Note: you must add a full line of space before and after lists for them to show up correctly
paragraph 1paragraph 2

paragraph 1

paragraph 2

[example link](https://brilliant.org)example link
> This is a quote
This is a quote
    # I indented these lines
# 4 spaces, and now they show
# up as a code block.

print "hello world"
# I indented these lines
# 4 spaces, and now they show
# up as a code block.

print "hello world"
MathAppears as
Remember to wrap math in $$...$$ or $...$ to ensure proper formatting.
2 \times 3 $$2 \times 3$$
2^{34} $$2^{34}$$
a_{i-1} $$a_{i-1}$$
\frac{2}{3} $$\frac{2}{3}$$
\sqrt{2} $$\sqrt{2}$$
\sum_{i=1}^3 $$\sum_{i=1}^3$$
\sin \theta $$\sin \theta$$
\boxed{123} $$\boxed{123}$$

Sort by:

Use the quadratic formula and solve for $$r$$.

In fact you get two answers, 13.5 and -6.5

- 2 years, 3 months ago

Thx man, ur awesome

- 2 years, 3 months ago

my pleasure :)

- 2 years, 3 months ago

@Jason Chrysoprase You may refer to this wiki to learn them more effectively. :V Anyways, one typo, your heading; change it into Help:Algebra currently it is Help:Algera, ;P

- 2 years, 3 months ago

Keep learning. Your passion in math will pay off.

- 2 years, 1 month ago