Could use some , got this question wrong twice-

(C)   y= 3cos(4x),

Step-by-step explanation:

When x=0, y=3. If we substitute x into the given equations, the possible answers are A,C or D.

Lets take C, y= 3cos(4x), and substitute x=π/2.

y= 3cos(4x) = 3cos(4*π/2)=3cos(2π)=3*1=3

This agrees with our graph. Choices B and D give wrong answers.

can you me with homework?

step-by-step explanation:

5x + 3y = - 4

step-by-step explanation:

the equation of a line in standard form is

ax + by = c ( a is a positive integer and b, c are integers )

express the line first of all in slope- intercept form

y = mx + c ( m is the slope and c the y-intercept )

to calculate m use the gradient formula

m = ( y₂ - y₁ ) / ( x₂ - x₁ )

with (x₁, y₁ ) = (7, - 3) and (x₂, y₂ ) = (4, - 8)

m = = -

y = - x + c ← is the partial equation

to find c substitute either of the 2 points into the partial equation

using (4, - 8 ), then

- 8 = - + c ⇒ c = -

y = - x - ← in slope-intercept form

multiply all terms by 3 to eliminate the fractions

3y = - 5x - 4 ( add 5x to both sides )

5x + 3y = - 4 ← in standard form