How to calculate 2x + 5x = 78

How to calculate 2x + 5x = 78

Hello!
2x+5x=78
7x=78
x=78÷7
x=78/7
I wish you a happy study_ O ha!

18x () - 4x () = 35 12.5x () - 6.5x () = 4.2 the number in each question () should be the same

18X( 2.5)-4X(2.5 )=35
12.5X( 0.7)-6.5X(0.7 )=4.2

(9x+8)(80-9x)=1855
(9x+8)(80-9x)=1855

(9x + 8) (80 - 9x) = two sides of the 1855 equation multiplied by - 1, we get (9x - 80) (9x + 8) = - 1855 (9x) "- 720x + 72x - 640 + 1855 = 081x" - 648x + 1215 = 0, simplify the coefficient 81 (X ") - 81 (8x) + 1200 + 15 = 081 (x") - 81 (8x)

Solve the inequality loga (1 − 1x) > 1

① When a ＞ 1, the original inequality is equivalent to the system of inequalities: 1 − 1 x ＞ 01 − 1 x ＞ A. therefore, 1 − a ＞ 1 X

Given the function f (x) = 2 ^ x + 1, the image of the function f - & sup1; is shifted two units to the left, and then one unit to the up, and the image of y = g (x) is obtained. The following results are obtained: (1) write the analytic expression of y = g (x); (2) find the minimum value of F (x) = g (X & sup2;) - F - & sup1; (x) and the value of X when the minimum value is obtained

First of all, the inverse function of this function is f - & sup1; so this function f - & sup1; = log2 (x-1) shifts this function to the left by two units to get f - & sup1; = log2 (x + 2-1) = log2 (x + 1), and then shifts this function to the upper by one unit, that is g (x) = log2 (x + 1) + 1 (x ＞ - 1) 2) g (X &

If the numbers represented by two points a and B on the number axis are a and B respectively, then the distance AB between two points a and B is equal to

AB = absolute value of (a-b)

How to determine the upper and lower line of integral when probability theory is used to calculate the marginal probability density?
Please understand the master to help me solve this problem, how to determine the up and down line y and 0,

0 and y are the left and right boundary of the region with non-zero joint probability density when y is specified. If we want to find the edge probability density of X, we need to use the upper and lower boundary. The economic mathematics team will help you to solve this problem, please evaluate it in time

Ask Daniel to help write a matlab drawing y = (sin (x)) ^ 2 / X / X * sin (4x) ^ 2

x=-1:0.1:1;
y=-1:0.1:1;
[X,Y]=meshgrid(x,y);
Z=sin(sqrt(X.^2+Y.^2))./sqrt(X.^2+Y.^2);
surf(X,Y,Z)
or
plot3(x,y,z,'r'）

Four seventh of () is equal to five eighth of 320
There should be a formula

320x(5/8)÷(4/7)
=200x(7/4)
=350

How to get the area formula of parallelogram s = ah is explained by translation method

The area of ∵ ABF is equal to the area of ∵ DCE, the area of ∵ parallelogram ABCD is equal to the area of rectangle afed, the area of ∵ rectangle s = ah, and the area of ∵ parallelogram s = ah