Question

1. A smaller square piece of plywood was cut from a larger square piece. If opposite ends of the remaining plywood have measures 2x + 5 cm and 2x – 5 cm, what expression represents its area?

2. A shipping container has a shape of a rectangular prism. If the area of its base is 49x2 + 14x + 4 sq. ft. and its height is 7x – 2 ft., what expression can be used to represent its capacity?​

Answer 1

Plywood1: x = width ; length = 2x

1) x (2x) = 4.5

2) 2x² - 4.5 = 0

a = 2 ; b = 0 ; c = -4.5

3) x = \frac{-b \pm\sqrt{b^2-4ac} }{2a} = \frac{0 \pm\sqrt{0-4(2)(-4.5)} }{2(2)}= \frac{\pm6}{4} = \boxed{\frac{3}{2}}x=

2a

−b±

b

2

−4ac

=

2(2)

0±

0−4(2)(−4.5)

=

4

±6

=

2

3

Plywood2: x = width ; length = 2x-1.4

1) x (2x-1.4) = 16

2) 2x² -1.4x -16 = 0

a = 2 ; b = -1.4 ; c = -16

3) x = \frac{-b \pm\sqrt{b^2-4ac} }{2a}=\frac{1.4 \pm\sqrt{1.96-4(2)(-16)} } < br / > {2(2)}=\frac{1.4 \pm11.4 }{4}=\boxed{3.2}x=

2a

−b±

b

2

−4ac

=

<

1.4±

1.96−4(2)(−16)

br/>2(2)=

4

1.4±11.4

=

3.2

Plywood3: x = width ; length = 5-x

1) x (5-x) = 6

2) -x² +5x -6 = 0

a = -1 ; b = 5 ; c = -6

3) x = \frac{-b \pm\sqrt{b^2-4ac} }{2a}=\frac{-5 \pm\sqrt{25-4(-1)(-6)} }{2(-1)}=\frac{-5 \pm1}{-2}x=

2a

−b±

b

2

−4ac

=

2(−1)

−5±

25−4(−1)(−6)

=

−2

−5±1

\boxed{x_1=3}

x

1

=3

\boxed{x_2=2}

x

2

=2

BRAIN LESS ANSWER