Answer this question (x −2)(x + 5) = 18

x=-7     x=4

Step-by-step explanation:

(x −2)(x + 5) = 18

Foil

x^2 +5x-2x-10 = 18

Combine like terms

x^2 +3x -10 =18

Subtract 18 from each side

x^2 +3x -28 = 0

Factor

What two numbers multiply to -28 and add to 3:   7 and -4

(x+7) (x-4) =0

Using the zero product property

x+7=0    x-4 =0

x=-7     x=4

system of linear equation

step-by-step explanation:

as given in the data

a= 20 , b= -12

let us suppose that it is a straight line equation

now we know the formula for the system of linear equation

b= ma + c )

here m is slope of a straight line which is equal to formula

m=   (ii)

and here c is a constant

now putting the value of a and b in equation (ii)

m=

m=

putting the value of a,b and m in equation (i) gives us

-12 = + c

-12=-12 + c

adding 12 to both sides

-12 +12 = -12 +12 +c

0 =c

or c=0

as the value of the constant is zero which gives us that it is a linear equation and this order pair satisfies the system of linear equations.