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1 year ago

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How do you solve f(x) = x2 + x - 20?

1 answer:

Darina [25.2K]1 year ago

4 0

$\huge \bf༆ Answer ༄$

Let's solve ~

${ \qquad{ \sf{ \dashrightarrow}}} \: \: \sf \: {x}^{2} + x - 20$

${ \qquad{ \sf{ \dashrightarrow}}} \: \: \sf \: {x}^{2} + 5x - 4x - 20$

${ \qquad{ \sf{ \dashrightarrow}}} \: \: \sf \:x(x + 5) - 4(x + 5)$

${ \qquad{ \sf{ \dashrightarrow}}} \: \: \sf \:(x + 5)(x - 4)$

It's factorized now ~ And if you want to find the zeros then equate the expression with 0.

And you will get ;

${ \qquad{ \sf{ \dashrightarrow}}} \: \: \sf \:x = - 5 \: \: and \: \: 4$

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The length of a rectangle is four times its width. If the area of the rectangle is 324m^2, find its perimeter.

Anuta_ua [19.1K]

Answer:

$perimeter=90$

Step-by-step explanation:

We know that the length is four times the width, so:

$l=4w$

We also know the area, which is 324 m². The formula for area:

$A=l*w$

Insert the known values:

$324=(4w)*w$

Solve for w. Simplify by removing parentheses:

$324=4w*w\\324=4w^2$

Divide 4 from both sides to isolate the variable:

$\frac{324}{4}=\frac{4w^2}{4} \\\\81=w^2$

Find the square root of both sides:

$\sqrt{81} =\sqrt{w^2} \\\\w=9$

The width is 9 m.

We know the width. Now find the length by using the area formula and inserting known values:

$324=l*9$

Solve for l. Divide both sides by 9:

$\frac{324}{9}=\frac{l*9}{9}\\\\ l=36$

The length of the rectangle is 36. (You can check: 4 times 9 is 36)

Now find the perimeter:

$P=2l+2w$

Insert values:

$P=2(36)+2(9)\\\\P=72+18\\\\P=90$

The perimeter is 90 m.

5 0

2 years ago

The cost of a book was decreased from 60 to 50 by what percent the price decrased with solution

Artist 52 [7]

Answer:

The price decreased by 16 1/3%, or approximately 16.3%

Step-by-step explanation:

Use the formula for percent change. If the answer is negative, it is a percent decrease. if the answer is positive, it is a percent increase.

percent change = (new price - old price)/(old price) * 100%

In this case, use:

new price = 50

old price = 60

percent change = (new price - old price)/(old price) * 100%

percent change = (50 - 60)/60 * 100%

percent change = -10/60 * 100%

percent change = -1/6 * 100%

percent change = -100/6% = -50/3% = -16 1/3%

The price decreased by 16 1/3%, or approximately 16.3%

7 0

2 years ago

This was given to me during a summative test and the teacher didn't bother giving me the correction. I just cannot figure it out

Dmitry [639]

Base be y

ATQ

$\\ \sf\longmapsto xy=6050\dots 1$

$\\ \sf\longmapsto 2(x+y)=220\implies x+y=110\dots 2$

Now

$\\ \sf\longmapsto (x+y)^2=x^2+y^2+2xy$

$\\ \sf\longmapsto 110^2-2(6050)=x^2+y^2$

$\\ \sf\longmapsto 12100-12100=x^2+y^2$

$\\ \sf\longmapsto x^2+y^2=0\dots(3)$

From all equations

$\\ \sf\longmapsto (x-y)^2=x^2+y^2-2xy$

$\\ \sf\longmapsto (x-y)^2=0-2(6050)$

$\\ \sf\longmapsto (x-y)^2=-12100$

$\\ \sf\longmapsto (x-y)=110\dots(4)$

Now

Adding 3 and 4

$\\ \sf\longmapsto 2x=220$

$\\ \sf\longmapsto x=110m$

One side won't be covered hence

y=2(110)=220m

7 0

2 years ago

Read 2 more answers

Reil [10]

///)(;-(()3)3)3$$/$1(-(-(-((1;1;/;;/ ye ya “3

6 0

2 years ago

Solve for x<br> -4+4x=16

vesna_86 [32]

X=5 because 4x5=20 and 20-4=16

7 0

2 years ago

Read 2 more answers