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3 years ago

Which equation has the same soultions as x^2+6×-7=0

1 answer:

4 0

$x^2+6x-7=0 \\ a=1 \\ b= 6 \\ c=-7 \\ \\ \boxed{\boxed{\Delta=b^2-4ac}} \\ \\ \Delta=6^2-4*1*(-7) \\ \Delta=36-(-28) \\ \Delta=64 \\ \Delta\ \textgreater \ 0 \Rightarrow \text{we have 2 solutions :} X_1 \ and X_2 \\ \\ \boxed{X_1= \frac{-b- \sqrt{\Delta} }{2a} } \Rightarrow X_1= \frac{-6-8}{2}=-7 \\ \\ \boxed{X_2= \frac{-b+ \sqrt{\Delta} }{2a} } \Rightarrow X_2= \frac{-6+8}{2} =1$

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30. Tina went to batting cages with $20. She rented a bat for $3. 25 and

aliya0001 [1]

Answer:

Step-by-step explanation:

Tina started with $20, but had to spend $3.25 on the bat.

$20-$3.25 = $16.75, which is all she has left for rounds.

Each round costs $3.00

$16.75 divided by $3.00 comes out to 5.58 rounds, but since she can't play 1/2 a round, that means she could only play 5 rounds

5 rounds X $3.00 per round comes to $15.00

8 0

3 years ago

Show that (a+b)^2=4p^2

Alja [10]

LHS :-

( a + b)²
(P + q + P - q)²
(2p)²
2²p²
4p² = RHS

8 0

2 years ago

5 over 12= x+1 over 4<br><br> please help!

SCORPION-xisa [38]

5/12=x+1/4

Equals 1/6

3 0

3 years ago

Read 2 more answers

Is 13 over 6 irrational number

mojhsa [17]

Answer: It is a rational number as irrational number is a number that cannot be expressed as a fraction for any integers.

Step-by-step explanation:

5 0

3 years ago

Find the critical values: a. Determine the critical value z????/2 that corresponds to a level of confidence of 87%. (2 pts). b.

larisa86 [58]

Answer:

a) $z_{\alpha/2}=-1.51$ and $z_{\alpha/2}=1.51$

b) $t_{\alpha/2}=-1.89$ and $t_{\alpha/2}=1.89$

c) $t_{\alpha/2}=-2.11$

d) $z_{\alpha/2}=-1.75$ and $z_{\alpha/2}=1.75$

Step-by-step explanation:

Part a

On this case the confidence is 87% or 0.87 so the significance level is $\alpha=1-0.87=0.13$ and $\alpha/2 =0.065$ . On this case we can assume that is a bilateral test or a confidence interval so we will have two critical values.

We need values a,b on the normal standard distribution such that:

$P(Z$ or $P(Z>b)=0.065$ and in order to find it we can use the following code in excel:

"NORM.INV(0.065,0,1)" or "NORM.INV(1-0.065,0,1)", and we see that the critical values $z_{\alpha/2}=-1.51$ and $z_{\alpha/2}=1.51$

Part b

On this case the confidence is 92% or 0.92 so the significance level is $\alpha=1-0.92=0.08$ and $\alpha/2 =0.04$ . On this case we can assume that is a bilateral test or a confidence interval so we will have two critical values.

First we need to calculate the degrees of freedom given by:

$df=n-1=15-1=14$

We need values b,c on the t distribution with 14 degrees of freddom such that:

$P(t_{(14)}$ or $P(t_{(14)}>c)=0.04$ and in order to find it we can use the following code in excel:

"T.INV(0.04,14)" or "T.INV(1-0.04,14)", and we see that the critical values $t_{\alpha/2}=-1.89$ and $t_{\alpha/2}=1.89$

Part c

The significance level is $\alpha=0.025$ and is a left tailed test. On this case we know that is a left tailed test so then we have just one critical value.

First we need to calculate the degrees of freedom given by:

$df=n-1=18-1=17$

We need a value c on the t distribution with 17 degrees of freddom such that:

$P(t_{(17)}$ , and in order to find it we can use the following code in excel:

"T.INV(0.025,17)", and we see that the critical values $t_{\alpha/2}=-2.11$

Part d

The significance level is $\alpha=0.08$ and $\alpha/2 =0.04$ . On this case we know that w ehave a two tailed proportion test, so we will have two critical values.

We need values a,b on the normal standard distribution such that:

$P(Z$ or $P(Z>b)=0.04$ and in order to find it we can use the following code in excel:

"NORM.INV(0.04,0,1)" or "NORM.INV(1-0.04,0,1)", and we see that the critical values $z_{\alpha/2}=-1.75$ and $z_{\alpha/2}=1.75$

6 0

3 years ago