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3 years ago

14

Jen factored x² - 4x - 21 as (x - 3)(x + 7) What did she do wrong?

2 answers:

Ivahew [28]3 years ago

6 0

Jen should have done (x+3)(x-7) bc the middle value of the original equation needs to be equal to the two numerical values added together from the factored equation

alexgriva [62]3 years ago

5 0

Answer:

She didn't put the sign's in the proper place, it should be ( x + 3 ) ( x - 7 )

Step-by-step explanation:

( x - 3 ) ( x + 7 ) = x² + 7x - 3x - 21 = x² + 4x - 21

( x + 3 ) ( x - 7 ) = x² - 7x + 3x - 21 = x² - 4x - 21

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Counterexamples and Logic Symbols HW

Mariana [72]

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2 years ago

1. Ada purchased a house using a fixed rate mortgage. The annual interest rate is 6.3%

vlabodo [156]

The monthly payment on the mortgage is option C) $2537.44

<u>Step-by-step explanation</u>:

Principal (P): $ 295,000
Rate (r): 6.3% = 0.063
Number of times compounded (n): 12months $\times$ 15 years = 180
Number of years = 15

The formula is A = P(1 + r/n)^nt

⇒ A = 295000(1+0.063/180)^(180 $\times$ 15)

⇒ A = 295000(180.063/180)^2700

⇒ A = 295000 (1.00035)^2700

⇒ A = 758854.5

Interest = Amount - Principle

⇒ 758854.5 - 295000

⇒ Interest = 463854.5

∴ The monthly payment for 15 years = 463854.5 / (15 $\times$ 12)

The monthly payment on the mortgage = 2576.9 (approximately option C)

8 0

3 years ago

A +-21 = -38<br><br>help me please

ivann1987 [24]

Answer:

A= -17

Step-by-step explanation:

A +-21 = -38

+21 +21

-38+21= -17

A= -17

5 0

2 years ago

Read 2 more answers

cylinder shaped can needs to be constructed to hold 200 cubic centimeters of soup. The material for the sides of the can costs 0

Dafna11 [192]

Answer:

Radius=2.09 cm

Height,h=14.57 cm

Step-by-step explanation:

We are given that

Volume of cylinderical shaped can=200 cubic cm.

Cost of sides of can=0.02 cents per square cm

Cost of top and bottom of the can =0.07 cents per square cm

Curved surface area of cylinder= $2\pi rh$

Area of circular base=Area of circular top= $\pi r^2$

Total cost,C(r)= $0.02\times 2\pi rh+2\pi r^2\times 0.07$

Volume of cylinder, $V=\pi r^2 h$

$200=\pi r^2 h$

$h=\frac{200}{\pi r^2}$

Substitute the value of h

$C(r)=0.02\times 2\pi r\times \frac{200}{\pi r^2}+2\pi r^2\times 0.07$

$C(r)=\frac{8}{r}+0.14\pi r^2$

Differentiate w.r.t r

$C'(r)=-\frac{8}{r^2}+0.28\pi r$

$C'(r)=0$

$-\frac{8}{r^2}+0.28\pi r=0$

$0.28\pi r=\frac{8}{r^2}$

$r^3=\frac{8}{0.28\pi}=9.095$

$r=(9.095)^{\frac{1}{3}}=2.09$

Again, differentiate w.r.t r

$C''(r)=\frac{16}{r^3}+0.28\pi$

Substitute the value of r

$C''(2.09)=\frac{16}{(2.09)^3}+0.28\pi=2.63>0$

Therefore,the product cost is minimum at r=2.09

h= $\frac{200}{\pi (2.09)^2}=14.57$

Radius of can,r=2.09 cm

Height of cone,h=14.57 cm

4 0

3 years ago

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Semmy [17]

3√32x^4z

= 3√(2^5)* x^4 *z

(Square rooting the terms)

= 3*2*2*x*x√2*z

=12x^2√2z

7 0

3 years ago

Read 2 more answers