How to calculate 76 plus 38 times 98 simply

76+38×98
=38×2+38×98
=38×（2+98）
=38×100
=3800

57 times 44 plus 44 times 44 minus 44
emergency

Is it 57 × 44 + 44 × 44-44? It evolved into 44 × (57 + 44-1) = 44 × 100 = 4400

Simple calculation 3.4 times 98 plus 6.8

3.4×98+6.8
3.4×98+3.4×2
=3.4×(98+2)
=3.4×100
=340

Simple calculation of 2.7 times 98 plus 27 times 0.2

=2.7 × 98 + 2.7 × 2 (here, the decimal point of 0.2 is "borrowed" to 27)
=2.7 × (98 + 2) (here, the law of multiplicative distribution)
=2.7×100
=270

9.4 times 0.98 + 6 times 0.098

9.4*0.98+6*0.098
=9.4*0.98+6*0.1*0.98
=(9.4+6*0.1)*0.98
=10 * 0.98
=9.8

It is known that the equation (a2-a) x2 + ax + A2-1 = 0 (1) when a is a value, the equation is a linear equation of one variable; (2) when a is a value, the equation is a quadratic equation of one variable; (3) when the equation has two real roots, one of which is 0, the value of a is obtained

(1) According to the characteristics of univariate quadratic equation, we get a2-a = 0, a = 0 or 1, when a = 0, the equation about X does not exist, so a = 1; (2) according to the characteristics of univariate quadratic equation, we get a2-a ≠ 0, a ≠ 1 and a ≠ 0; (3) substituting x = 0 into the original equation, we get A2-1 = 0, when a = ± 1, a = 1, the equation about X does not exist, so a = - 1

The red side and the blue side have an exercise. The red side scout's Pony investigates 400 meters away from the east-west highway and finds a blue side car speeding on the highway. He quickly takes out the infrared range finder. The distance between the car and him is 400 meters. After 10 seconds, the car is 500 meters away from him. Then the speed of the blue side car is (&# 160; &# 160; &# 160; &# 160; &# 160; &# 160; &# 160; &# 160; &# 160;) km / h

Using Pythagorean theorem
Let the speed of the car be X
500^2-400^2=10X
10X=900
X=90
So the speed of the car is 90 meters per second, 324 kilometers per hour
Upstairs did not want to come here, the distance is straight line distance, so it can form a triangle

Univariate quadratic equation (19:17:9:55)
A watermelon operator bought a batch of small watermelons at the price of 2 / kg and sold them at the price of 3 yuan / kg, which could sell 200 kg per day. In order to promote sales, the operator decided to sell them at a lower price. After investigation, it was found that for every 0.1 yuan / kg reduction in price, 40 kg more could be sold per day. In addition, the daily fixed cost such as rent was 24 yuan, How much should the price of small watermelon be reduced per kilogram

Suppose: the price of watermelon is reduced by X Yuan / kg (3-x-2) × (200 + X / 0.1 × 40) = 200 + 24 (1-x) (50 + X / 4) = 224 50 + 0.25x-50x-0.25x & sup2; = 2240.25x & sup2; + 49.75x = - 1740.25x & sup2; + 49.75x + 174 = 0 X & sup2; + 199X + 696 = 0 X1 = 0.3x2 = 0.2

Given that y = 2x2 + 7x-1, when what is the value of X, is the value of y equal to that of 4x + 1? When what is the value of X, the value of Y and the value of x2-19 are opposite to each other?

∵ y = 2x2 + 7x-1, the value of Y is equal to that of 4x + 1, ∵ 2x2 + 7x-1 = 4x + 1, that is, 2x2 + 3x-2 = 0, that is, (2x-1) (X-2) = 0, the solution is X1 = 2, X2 = 12; ∵ the value of Y is opposite to that of x2-19, ∵ 2x2 + 7x-1 + (x2-19) = 0, the solution is (3x-5) (x + 4) = 0, the solution is X1 = - 4, X2 = 53

Several math problems. (17:16:4:11)
1. The retail price of a drug after two price cuts is 81% of that before price cuts, with an average price cut ()
2. For the solution of equation 49x2-98x-1 = 0
A has no solution; B has two positive roots; C has two negative roots; D has one positive root and one negative root
3. If x2-2 (M + 1) x + 4 is a complete square, then M = ()
4. If the sum of squares of two continuous natural numbers is 112 less than their sum of squares, then the two natural numbers are ()

(1) If the original price is 100, the price after price reduction is 81, and the percentage of price reduction is X
Then the square of equation 100 (1-x) = 81
Then x = 1
(2) Can't see the title clearly?
（3）
(4) Square of X + square of (x + 1) - (x + X + 1) = - 112
I'll figure it out by myself. There's no scribble beside

How to calculate 76 plus 38 times 98 simply