Answer:
x = 3 and x = -7
Step-by-step explanation:
The given quadratic equation is
. We need to find the solution of this equation.
If the equation is in the form of
, then its solutions are given by :

Here, a = 1, b = 4 and c = -21
Plugging all the values in the value of x, such that :

So, the solutions of the quadratic equation are 3 and -7.
Let t represent Todd's age now.
.. 4(t -3) -(t -3) = 81 . . . . . . 3 years ago, their differnce in ages was 81.
.. 3t -9 = 81
.. t = (81 +9)/3 = 30
Todd is 30 now.
_____
You can also work this by considering "ratio units." 3 years ago, the ratio of their ages was 4:1, a difference of 3. That difference corresponds to 81 years, so each "ratio unit" represents 81/3 = 27 years. Todd's age then was 1 ratio unit, 27 years. Now, Todd's age is 30.
Subtract negative = add
88 + 35 = 123
The solution is 123
5a) rotational symmetry is 2 because it can be rotated only 2 times before it turns to the original form.
b) perimeter is the total surface of all the sides so, because we are given a scale of 1 unit = 1cm then our measurements would be: 4cm + 3cm + 2cm + 1cm + 4cm + 3cm + 2cm + 1cm = 20cm.
c) To workout the area we need to divide the irregular shape into separate regular shapes<em>.</em><em> </em><em>the </em><em>diagram</em><em> </em><em>will</em><em> </em><em>help</em><em> </em><em>you</em><em>!</em><em> </em>Shape 1 is a rectangle so, area = L × W = 3 × 2 = 6cm. Shape 2 is a square so, area = side² = 2² = 4cm. Shape 3 is the same as shape 1 so the area is 6cm. Now to find the area of the whole shape we add these values so, 6+4+6= area of shape = 16cm.
d) <em>The</em><em> </em><em>dia</em><em>gram</em><em> </em><em>will</em><em> </em><em>show</em><em> </em><em>the</em><em> </em><em>answer</em><em>!</em>