find an expression for the area of a rectangle of sides 2x+3 and x-1 given that the perimeter is 28cm what is the value of x

4cm

Step-by-step explanation:

Given data

L=(2x+3)

W=(x-1)

P=28cm

A= L*W

A= (2x+3)*(x-1)

open bracket

A= 2x^2-2x+3x-3

collect like terms

A= 2x^2+x-3

P= 2L+2W

P= 2*(2x+3)+2(x-1)

P= 4x+6+2x-2

collect like terms

P= 6x-4

but p= 28

28= 6x-4

28-4= 6x

24= 6x

x= 24/6

x= 4cm

Hence x= 4cm

b. x- 48 =120

step-by-step explanation:

-3

step-by-step explanation:

a drawing really does here:

so i draw the horizontal line y=2 and the vertical line x=-2 at this intersection i put b (this is where my right angle is going to be).   so point b is at (-2,2).   point a is 5 units long and is also on y=2 so this point has to be (3,2) or (-7,2) -doesn't matter i will go with (3,2).

now we know c is at (-2,y) we don't know the y yet bet we know that c is on x=-2.

we have the area of the triangle is .5bh=12.5

we know the base length is 5 (ab)

we have the height is (2-y) if you look at your

plug in

.5(5)(2-y)=12.5

solve for y to get the y-coordinate for c

2.5(2-y)=12.5

divide both sides by 2.5 giving:

2-y=5

now subtract 2 on both sides

-y=3

y=-3