The way these equations are arranged helps.
First only deal with the left handside.
<span>X^2+20x= (x+a)^2 -b where we are looking for a,b
You need to know the general formula for (x+a)^2=x^2+2ax+a^2
20x = 2*10x so a will be 10
(x+10)^2= x^2+20x+100
Now lets look at the original question:
</span><span>X^2+20x=10
we know now that </span>(x+10)^2= x^2+20x+100
Thus X^2+20x=(x+10)^2 -100
So X^2+20x=10 becomes
(x+10)^2 -100 =10
(x+10)^2=110
For the other question you need to follow the same logic.
Answer:
x = -7
Step-by-step explanation:
6+2x=-8
2x=-14
x = -7
Step-by-step explanation:
x² + 7x − 8 = 0
(x + 8) (x − 1) = 0
x = -8 or 1
Answer:
36 minutes
Step-by-step explanation:
It takes 45 mins to deliver paper on her route.
Let X be the amount of time it takes the brother to complete the route.
The brother works at the rate of 1/x route per min
The girl works at the at the rate of 1/45 route per min
Girl and brother working together works at rate of 1/20 route per min
1/x + 1/45 = 1/20
Multiply through by 180x
180 + 4x = 9x
4x - 9x = -180
-5x = -180
x = -180 / -5
x = 36 mins.
It takes the brother 36 minutes to complete route alone.
100?
or actualy its 180 degrees C
