What ordered pair is a solution of the system of equations y=x^2-x-20 and y=3x-15?

Hey there!!

Equations given :

y = x² - x - 20 ( 1 )

y = 3x - 15 ( 2 )

Now, lets first solve for the 1st equation ...

... x² - x - 20

We can write -x as -5x + 4x

... x² + 4x - 5x - 20

... x ( x + 4 ) - 5 ( x + 4 )

... ( x - 5 ) ( x + 4 )

y = ( x - 5 ) ( x - 4 )

Now, let's solve the second equation ...

y = 3x - 15

... y = 3 ( x - 5 )

We have two equations, now getting them together..

3 ( x - 5 ) = ( x - 5 ) ( x - 4 )

Divide by x-5 on both sides

3 = x - 4

Add 4 on both sides

x = 7

The value of x is 7

Now substituting this, we get the value of y

We have,

y = 3x - 15

... y = 3(7 ) - 15

... y = 21 - 15

... y = 6

Hence, the ordered pair is ( 7 , 6 )

Hope my answer helps!

something that characterises a right triangle is the fact that we may use pythagoras' theorem to find any one of its sides given that we have the length of the other two sides. here, we have the length of the hypotenuse, √(87) yd, and one other side, √(23) yd, thus we can easily find the length of the remaining side using pythagoras' theorem as defined below:

c^2 = a^2 + b^2, where c is the length of the hypotenuse, and a and b are the lengths of the other two sides.

thus, given that c = √(87) and a = √(23), we may substitute these into the formula we defined above to get:

c^2 = a^2 + b^2

(√87)^2 = (√23)^2 + b^2 (substitute c = √87 and a = √23 into the equation)

87 = 23 + b^2 (evaluate (√87)^2 = 87 and (√23)^2 = 23 - remember that the square root of a number, squared will equal that very same number)

64 = b^2 (subtract 23 from both sides)

√64 = b (take the square root of both sides)

8 = b (evaluate √64 = 8)

therefor, the length of the unknown leg in the right triangle is 8 yd (first answer).