For this case we have to:
x: Represents the unknown number
y: Represents the exponent of base 10
So, considering a system of equations we have:

From the first equation we have:

Substituting in the second equation:

We choose the positive value:

So, the number is 0.4.
So:

Thus, the exponent is 5.
Answer:
Yara use 0.4 and
11. You’ve done it correctly
12. Let x^2=y
y^2+13y+40=0
(y+8)(y+5)=0
y=8, 5
Since y=x^2
x^2=8 x^2=5
x=+/-√5 x= +/-2√2
13. x^4-x^2-x^2-8=0
x^4-2x^2-8=0
let x^2=y
Y^2-2y-8=0
(y-4)(y+2)=0
y=4, -2
Since y=x^2
X^2=4 X^2=-2
X= +/- 2 This wouldn’t be a real solution
14. It’s pretty much the same process, just substitute y in for x^2. If you’re confused feel free to ask and I can do it, or you can put it through Photomath
15. You’re on the right track so I’m just going to continue from where you left off
x^2(4x+5)-4(x+5)=0
(x^2-4)(4x+5)=0
x= +/- 2 4x=5
x=5/4 or 1 1/4
Hope this helped :)
Answer:

Step-by-step explanation:
The model shows that there are 40 tiles which were divided into 4 per group. This results into 10 groups. That is:

Therefore, the expression modeled by the arrangement of the tiles is 
Answer:
Graph B shows function f of x equals 4 multiplied by 3 to the power of negative x.
Step-by-step explanation:
is the value 4 times three raised to the negative x. Graph B is the best representation.
Answer:
1/11 if you mean the proportion of the cost of the topping to the cost of the whole pizza
Step-by-step explanation: