Using the linear combination method, what is the solution to the system of linear equations 5x+3y=-10 and -20x-7y=15

The x-coefficients have a nice ratio, and one of them is negative. That makes it easy to eliminate x by multiplying the first equation by 4 and adding the second equation:

4(5x+3y) +(-20x-7y) = 4(-10) +(15)

5y = -25 . . . . . simplify

y = -5 . . . . . . . divide by 5

Substitute this result into either equation to find x. I choose to use the first equation.

5x +3(-5) = -10

5x = 5 . . . . . . add 15

x = 1 . . . . . . . divide by 5

The solution is (x, y) = (1, -5).

d) by the cross product property, ab^2 = bc multiplied by ad

step-by-step explanation:

we are given

in the given triangle abc

angle a is 90° and segment ad is perpendicular to segment bc

we can see that

triangle(abc) and triangle(abd) are similar because they have common side and same angle (90 degree)

so, triangles(abc) and abd are similar

since, they are similar

so, the ratio of their sides must be equal

we get

now, we can cross multiply

and we get

so, this could be step to prove it