Answer: what??
Step-by-step explanation:
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>
Because it's decreasing, you use the formula (1-x/100)y with x the percentage decreased which is here 40, and y the number decreased which is here 90
So we get
(1-40/100) * 90
(100/100 - 40/100) * 90
60/100 * 90
5400/100
54
So 90 decreased by 40% is 54
Hope this Helps :)
Let's make an equation. T will be the number.
(T+5)/4=7
Let's multiply both sides by 4 to get T by itself.
T+5=28
Subtract 5 from both sides.
T=23
Your number is 23.
