The first volume of mathematics of junior high school

The first volume of mathematics of junior high school

The first problem is equal to 10, the second problem is equal to 50, according to the multiplication of two numbers, the same sign is positive, the different sign is negative, judge - 4x (- 5) = 20, then x0.25, the third problem is equal to 15, the fourth problem is equal to - 4, this problem can also use the law of distribution by multiplication, the fifth problem is equal to - 48, this problem can also use the multiplication score

39 out of 79 times 80

Original formula = 39 / 79 x 80
=39/79 x (79+1)
=39/79 x 79 + 39/79 x 1
=39 + 39/79
=39 and 39 / 79

Answers to the English assessment manual for Grade 8 Volume 2

1. Abbad A-B C-F D-E V-F 2. What how what though and some others, please come to me

Let B know that the square of AB is less than 0, a + B is greater than 0, and the absolute value of a = 1, the absolute value of B = 2, and find the absolute value of a - negative 3 + [B-1]
Given that a and B are opposite to each other, C and D are reciprocal to each other, the absolute value of M is 4, and the value of the 2010 power of formula [a + b] - the 2009 power of [a + B-Cd] of M is calculated

The square of AB is less than 0, a + B is greater than 0, and the absolute value of a is 1, the absolute value of B is 2,
A = - 1, B = 2,
The absolute value of a - negative 3 + [B-1] = - 1-3 + 1 = - 3
2010 power of [a + b] - 2009 power of [a + B-Cd] of M
=2010 power of 0 - (- 1) 2009 power / 4
=1/4

How to solve the two equations 3x + y = 82, 11x-9y = 22,

Multiply both sides of the first equation by 9
27x+9y=738
Add to the second equation
27x+9y+11x-9y=760
38x=760
x=20
Substitute x = 20 into the first equation
60+y=82
y=22
So x = 20, y = 22

Given the square of a + 2A + 3 = 5, find the square of 3A + 6A

The square of a + 2A + 3 = 5
a²+2a=2
3a²+6a
=3(a²+2a)
=3×2
=6

Given the vector a = (2, t), B = (1, 2), if t = T1, a ∥ B; t = T2, a ⊥ B, then ()
A. t1=-4，t2=-1B. t1=-4，t2=1C. t1=4，t2=-1D. t1=4，t2=1

The vector a = (2, t), B = (1, 2), if t = T1, a ∥ B, ∥ T1 = 4; if t = T2, a ⊥ B, T2 = - 1, so select C

Give an example of the effect of the direct influence of the three elements of power
As above

It can only be lifted if the lifting force is greater than its own gravity
Push a car in different directions, the effect is different
Action point: the closer the door closer the door closer the door closer the door closer the door closer the door closer the door closer the door closer the door closer the door closer the door closer the door closer the door closer the door closer the door closer the door closer the door closer the door closer the door closer the door closer the door closer the door closer the door closer

0.5x÷128×6＝7．

0.5x÷128×6=7，      12x×28×6=7，        12x×168=7，   12x×168÷168=7÷168，             12x=124，          12x×2=124×2，                x=112．

One fraction minus one monomial, then is this formula still a fraction

Calculate
As long as the denominator has unknowns, no matter how many terms are fractions