4. Write the number sentences for the following problems: a) I multiply a number by 4 and then add 3 . The result is 31 . b) I staried with a number, mutipiy it by 3 , subtract 20 and my result is the number I started with, (2) c) Given that the angles of a triangle are \( x^{4}, 3 x \), and \( (x-30)^{2} \). Find \( x \) and the size of the three angles

a) Let the number be represented by \( n \). a) I multiply a number by 4 and then add 3. The result is 31. The number sentence for this problem is: \[ 4n + 3 = 31 \] b) I started with a number, multiply it by 3, subtract 20, and my result is the number I started with. The number sentence for this problem is: \[ 3n - 20 = n \] c) Given that the angles of a triangle are \( x^{4}, 3x \), and \( (x-30)^{2} \). Find \( x \) and the size of the three angles. The sum of the angles of a triangle is always 180 degrees. So, we can set up the equation: \[ x^{4} + 3x + (x-30)^{2} = 180 \] Now, we need to solve this equation to find the value of \( x \) and the size of the three angles.