Clara forgot to distribute the - sign to- (2b-r) through all the terms the answer would be 6b+3r
It is true, how??Here is explanation:
Consider a quadrilateral ABCD .Join diagnol AC so two triangles ABC & ACD will form.
Sum of interior angles of ABC is 180 and that of ACD is 180 as well.So, the total sum of the interior angles of ABC & ACD is 360 which is the sum of interior angles of quadrilateral itself.
Answer:

Step-by-step explanation:
1) Rewrite
in the form
, where a = y and b = 1.

2) Use Square of Difference:
.

3) Factor
.
1 - Ask: Which two numbers add up to 6 and multiply to -7?
-1 and 7
2 - Rewrite the expression using the above.

Outcome/Result: 
4) Rewrite the expression with a common denominator.

5) Expand.

6) Collect like terms.

7) Simplify
to 

Answer:
3mph
Step-by-step explanation:
his speed per hour will be 3 miles per hour
Answer:
20√3 cm
Step-by-step explanation:
Altitude of an equilateral triangle splits it into 2 equal right triangles, it bisects the base and the angle opposite to the base.
<u>Let the altitude be x. Then as per Pythagorean theorem:</u>
- x² = 40² - (40/2)²
- x²= 1600 -400
- x²= 1200
- x= √1200
- x= 20√3 cm
<u>Correct choice is</u> the second one