5 t-shirt cost R120.how much will 9t-shirt cost

Write a quadratic equation given the roots -1/3 and 5, show your work

Travka [436]

$\boxed{(x - a)(x - b) = 0}$

The equation above is the intercept form. Both a-term and b-term are the roots of equation.

$x = - \frac{1}{3} \\ x = 5$

These are the roots of equation. Therefore we substitute a = - 1/3 and b = 5 in the equation.

$(x + \frac{1}{3} )(x - 5) = 0$

Here we can convert the expression x+1/3 to this.

$x + \frac{1}{3} = 0 \\ 3x + 1 = 0$

Rewrite the equation.

$(3x + 1)(x - 5) = 0$

Simplify by multiplying both expressions.

$3 {x}^{2} - 15x + x - 5 = 0 \\ 3 {x}^{2} - 14x - 5 = 0$

Answer Check

Substitute the given roots in the equation.

$3 {(5)}^{2} - 14(5) - 5 = 0 \\ 75 - 70 - 5 = 0 \\ 75 - 75 = 0 \\ 0 = 0$

$3( - \frac{1}{3} )^{2} - 14( - \frac{1}{3}) - 5 = 0 \\ 3( \frac{1}{9} ) + \frac{14}{3} - 5 = 0 \\ \frac{1}{3} + \frac{14}{3} - \frac{15}{3} = 0 \\ \frac{15}{3} - \frac{15}{3} = 0 \\ 0 = 0$

The equation is true for both roots.

Answer

$\large \boxed {3 {x}^{2} - 14x - 5 = 0}$

8 0

2 years ago

X^2-8x+10=-4 quadratic equation written in standard form

ASHA 777 [7]

Rewriting the formula in standard form would be x^2-8x+14=0

3 0

2 years ago

Three students, Matthew, Thompson and Amos shared #15000 in the ratio of 5:2:x respectively. If Matthew's share is 7500, calcula

jasenka [17]

Answer:

The value of x is 3.

Step-by-step explanation:

Matthew earned 7500 of 15000, which is exactly half the total amount, meaning that the fraction corresponding to his earnings is 1/2.

Rate of 5:2:x, with number 5 corresponding to Matthew, mean that his fraction of the earnings, in function of x is given by:

$\frac{5}{5 + 2 + x} = \frac{5}{7 + x}$

Both fractions are equal, so:

$\frac{5}{7 + x} = \frac{1}{2}$

Applying cross multiplication:

$7 + x = 10$

$x = 10 - 7$

$x = 3$

The value of x is 3.

5 0

2 years ago

A study of the relationship between age and various visual functions (such as acuity and depth perception) reported the followin

maks197457 [2]

Answer:

(a) $\sum x_i=56.68$ and $\sum x_i^2=197.46$

(b) The sample variance is $s^2=0.530$ and the sample standard deviation is $s=0.728$

Step-by-step explanation:

(a)

The sum of these 17 sample observations is

$\sum x_i=2.79\:+2.57+\:2.73\:+3.75\:+2.27+\:2.75+\:4.00+\:4.22+\:3.88+\:4.35+\:3.41+\:4.57+\:2.38+\:3.73\:+2.75+\:3.47+\:3.06\\\\\sum x_i=56.68$

and the sum of their squares is

$\sum x_i^2=2.79^2\:+2.57^2+\:2.73^2\:+3.75^2\:+2.27^2+\:2.75^2+\:4.00^2+\:4.22^2+\:3.88^2+\:4.35^2+\:3.41^2+\:4.57^2+\:2.38^2+\:3.73^2\:+2.75^2+\:3.47^2+\:3.06^2\\\\\sum x_i^2=197.46$

(b)

The sample variance, denoted by $s^2$ , is given by

$s^2=\frac{S_{xx}}{n-1}$

where $S_{xx} =\sum x_i^2-\frac{(\sum x_i)^2}{n}$

Applying the above formula we get that

$S_{xx}=197.46-\frac{(56.68)^2}{17}\\\\S_{xx} =8.482$

$s^2=\frac{8.482}{17-1}=0.530$

The sample standard deviation, denoted by s, is the (positive) square root of the variance:

$s=\sqrt{s^2}$

Applying the above formula we get that

$s=\sqrt{0.530}=0.728$

3 0

2 years ago

A data set includes weights of garbage discarded in one week from 62 different households. The paired weights of paper and glass

lara [203]

Answer:

Because the absolute value of the test statistic is less than the positive critical value, there is not enough evidence to support the claim that there is a linear correlation between the weights of discarded paper and glass for a significance level of α = 0.05.

Step-by-step explanation:

The correlation matrix provided is:

Variables Paper Glass

Paper 1 0.1853

Glass 0.1853 1

Te hypothesis for the test is:

H₀: ρ = 0 vs. H₀: ρ ≠ 0

The test statistic is:

r = 0.1853 ≈ 0.185

As the alternate hypothesis does not specifies the direction of the test, the test is two tailed.

The critical value for the two-tailed test is:

$r_{\alpha/2, (n-2)}=r_{0.05/2, (62-2)}=r_{0.05/2, 60}=0.250$

The conclusion is:

Because the absolute value of the test statistic is less than the positive critical value, there is not enough evidence to support the claim that there is a linear correlation between the weights of discarded paper and glass for a significance level of α = 0.05.

6 0

3 years ago

5 t-shirt cost R120.how much will 9t-shirt cost​

5 t-shirt cost R120.how much will 9t-shirt cost