Question #e94e0
3 Answers
Explanation:
color(blue)(r^2=-14+9r
Bring everything to the left hand side
Now, this is a quadratic equation. Solve it by using the Quadratic formula
color(brown)(x=(-b+-sqrt(b^2-4ac))/(2a)
Where
Now, there are two solutions for
color(purple)(r=(9+5)/2=14/2=7)
color(violet)(r=(9-5)/2=4/2=2)
Hope this helps..! :)
Explanation:
Re-arrange it into general form first:
It does not matter at all what the variable is!
This means:
The quadratic formula is:
Use the values for
There are two possible answers for
We could also have solved the original equation by finding the factors.
Explanation:
"rearrange and equate to zero"
rArrr^2-9r+14=0
"compare to the standard form " ax^2+bx+c=0
"here " a=1, b=-9, c=14
rArrr=(-b+-sqrt(b^2-4ac))/(2a)
color(white)(rArrr)=(-(-9)+-sqrt((-9)^2-(4xx1xx14)))/2
color(white)(rArrr)=(9+-sqrt(81-56))/2=(9+-sqrt25)/2
rArrr=(9+5)/2=7" or " r=(9-5)/2=2