Can someone pls pls help me ?

a = 9

Step-by-step explanation:

this shape is an isosceles trapezoid where the pair of non-parallel sides are equal; therefore we can set up this equation to find 'a'

P = a + a + 2 + 8

28 = 2a + 10

18 = 2a

a = 9

Check:

9(2) + 2 + 8 = 28

18 + 10 = 28

28 = 28

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.