2 / 3 plus the quotient of 7 / 10 divided by 7 / 9, what is the product of the sum multiplied by 1 / 4?

2 / 3 plus the quotient of 7 / 10 divided by 7 / 9, what is the product of the sum multiplied by 1 / 4?

[2／3﹢﹙7／10﹚÷﹙7／9﹚] × ﹙1／4﹚
=[2／3﹢9／10] × 1／4
=47／120
A: the product is 47 / 120

2.5 times 3.9 divided by 1.3. What is the product ratio of 2.9 and 5.1?

(2.5 × 3.9÷1.3):(2.9+5.1)
=7.5:8
=15:16

(1) What is the product of 2 / 3 plus 1 / 4 divided by 75% and multiplied by 25%? (2) One sixth of the number of B is 10 less than 25% of the number of A. the number of B is 90. What is the number of a?

（1）（2/3+1/4÷75%） × 25%
=（2/3+1/3） × 25%
=1 × 25%
=25%
（2）（90 × 1/6+10）÷25%
=（15+10）÷25%
=25÷25%
=100

1. 25% of a number is 50% of 200. What is 3 / 4 of this number? What is the product of 2.3/8 times 3 / 5, plus the quotient of 3 / 20 divided by 1 / 4? 3.96 1 / 8 is 78 less than 9 / 20 of a number. Find this number?

chenbin8391902,
1、200 × 50%÷25% × 3/4
=400 × 3/4
=300
A: 25% of a number is 50% of 200, and 3 / 4 of this number is 300
2、3/8 × 3/5＋3/20÷1/4
=9/40+3/5
=9/40+24/40
=33/40
A: the product of 2.3/8 times 3 / 5, plus the quotient of 3 / 20 divided by 1 / 4, is 33 / 40
3、（96 × 1/8+78）÷9/20
=（12+78）÷9/20
=90÷9/20
=100
A: 96 1 / 8 is 78 less than 9 / 20. This number is 200

Root formula of univariate quadratic equation Root 2x square + 3x - root 2 = 0, please use the formula method to calculate. Requirements: write out the detailed process to calculate the univariate quadratic equation, urgent

a=√2,b=3,c=-√2
△=b ²- 4ac=9+8=17
So x = (- 3 ±√ 17) / (2 √ 2)
So x = (- 3 √ 2 - √ 34) / 4, x = (- 3 √ 2 + √ 34) / 4,

Formula for finding imaginary root of univariate quadratic equation

ax^2+bx+c=0
Δ= b^2-4ac
When Δ< At 0,
Root is (- B ±√ (- Δ） i）/2a
Where I is imaginary unit