Equation: 4x + 7 = 3(2x - 5)
Step-by-step solution:
• Expand brackets
-> 4x + 7 = 6x - 15
• Move x variable to a side and the numbers to another
-> 4x - 6x = -15 - 7
• Solve
-> -2x = -22
• Multiply both sides by (-1)
-> -(-2x) = -(-22)
-> 2x = 22
• Divide both sides by 2
-> x = 22/2
-> x = 11
• Justification
-> Put x = 11 in original equation
-> 4(11) + 7 = 3( 2(11) - 5)
-> 44 + 7 = 3(22 - 5)
-> 51 = 3(17)
-> 51 = 51
-> 51 - 51 = 0
-> 0 = 0
Since both sides are equal to each other, the answer to the equation is correct.
I don't know Sam's equation so I'm not gonna answer that.
Answer:
x = 114°
Step-by-step explanation:
The exterior angle of a triangle is equal to the sum of the 2 opposite interior angles, thus
x + 18° = 132° ( subtract 18° from both sides )
x = 114°
We are given that the angle a is the right angle. So let
us work from this.
ab = 12 (the vertical side of the triangle)
bc = 13 (which if drawn can be clearly observed to be the
hypotenuse) = the side opposite to angle a
ca = 5 (the horizontal side of the triangle)
Since we are to find for the cosine ratio of angle c or
angle θ, therefore:
cos θ = adjacent side / hypotenuse
cos θ = ca / bc
cos θ = 5 / 13
Check out the attached image below for the illustration
of the triangle.
(4a + 6b) x (2a - 2b)
the answer would be 8a2 + 4ab - 12b2
