#5 Test question 7th grade math

Which equation can be solved by using this expression?

Marat540 [252]

Answer:

The correct answer option is B. 2 = 3x + 10x^2

Step-by-step explanation:

We are to determine whether which of the given equations in the answer options can be solved using the following expression:

$x=\frac{-3 \pm\sqrt{(3)^2+4(10)(2)} }{2(10)}$

Here, $a = 10, b = 3$ and $c=-2$ .

These requirements are fulfilled by the equation 4 which is:

$12=3x+10x^2$

Rearranging it to get:

$10x^2+3x-2=0$

Substituting these values of $a,b,c$ in the quadratic formula:

$x= \frac{-b \pm \sqrt{b^2-4ac} }{2a}$

$x= \frac{-3 \pm\sqrt{(3)^2-4(10)(-2)} }{y}$

3 0

2 years ago

The math club sells candy bars an d drinks during football games. • 60 candy bars and 110 drinks will sell for $265. • 120 candy

Sedbober [7]

We can set up a system of equations to solve this.

120b + 90d = 270
60b + 110d = 265

To cancel out b, first make the b terms equal.

60b · 2 + 110d · 2 = 265 · 2
120b + 220d = 530

Now subtract the equations.

120b + 90d = 270
-120b + 220d = 530
---------------------------
-130d = -260

Solve for d.

-130d/-130 = -260/-130
d = 2

Now put the value of d in one of the equations.

60b + 110d = 265
60b + 110 · 2 = 265
60b + 220 = 265
60b + 220 - 220 = 265 - 220
60b = 45
60b/60 = 45/60
b = 0.75

Each candy bar sells for $0.75

Hope this helps! :)

7 0

2 years ago

PLZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ HELP ME THIS IS SO CONFUSING AND I DON'T UNDERSTAND ANYTHING PL

Leto [7]

Answer:

i got -2y + 3/2 x + 7/4

so I think is d

5 0

3 years ago

ASAP PLEASE HELP!! 50 POINTS

svetlana [45]

Answer/Step-by-step explanation:

Total Distance = 3Ft

a) Determine the amplitude and period of a sinusoidal function that models the bobbing buoy.

Amplitude = 3/2 = 1.5 period = 10 second

$\frac{0}{1} =\frac{2\pi }{b}$ $b=\frac{\pi }{5}$ No ph. Shift

b) Write an equation of a function that models the buoy with x=0 at its highest point.

y= 1.5 cos ( $\frac{\pi }{5} x$ )

3 0

2 years ago

Janeel has a 10-inch by 12-inch photograph. She wants to scan the photograph, then reduce the result

Vaselesa [24]

Complete Question:

Janeel has a 10 inch by 12 inch photograph. She wants to scan the photograph, then reduce the results by the same amount in each dimension to post on her Web site. Janeel wants the area of the image to be one eight of the original photograph. Write an equation to represent the area of the reduced image. Find the dimensions of the reduced image.

Correct Answer:

A) $(10-x)(12-x)=15$