Rita has a sister named Gabriela who is 4 years older than she is. The product of their ages is 21. Write an equation to find their ages.

Step-by-step explanation:

let Rita = R

Let Gabriela = G

so we have

G ×R = 21

G= R + 4

(R+4)(R) = 21

R^2+4R -21=0

answer: 204

step-by-step explanation:

we are told that the revenue is

x⋅(4080−10x)=−10x^2+4080x

this is a quadratic function, so to maximize it we should find the x-value of its vertex. recall that the x-value of the vertex of the parabola ax^2+bx+c is given by the formula −b/2a.

so in this case, we have a=−10 and b=4080, so the x-value of the vertex is

−b/2a= −(4080)/2(−10)=204

130 degrees. i have no other way to explain