Answer:

Step-by-step explanation:

Expand the brackets.

Add -9x and 5x

Add 4x and 6x on both sides.

Add the like terms.

Divide 12 into both sides.


Here you have an equilateral triangle. Because of this you know that all angles are also the same as each other. We know that the angles in an equilateral triangle are 60°.
so let's set 7x + 4 = 60
Subtract 4 from both sides: 7x = 56
Divide both sides by 7: x = 8
Answer:
<u>The solutions to this quadratic equation are 10 and 3.</u>
Step-by-step explanation:
1. Let's recall the formula for solving this type of equations, called quadratic equations:
x = ( - b +/- √ b² - 4ac)/ 2a
The equation given is x2 – 13x + 30 = 0,
where a = 1, b = - 13 and c = 30
Now replacing with the real values, we have
x = [ - (-13) +/- √ (-13)² - 4 * 1 * 30] / 2 * 1
x = [ 13 +/- √ 169 - 120] / 2
x = [13 +/- √ 49]/ 2
x = [ 13 +/- 7 ]/ 2
<u>x₁ = 13 + 7/2 = 20/2 = 10</u>
<u>x₂ = 13 - 7/2 = 6/2 = 3</u>
You would use 72/9 , ( division ).